Going through my grandpa's effects the other day and found a framed photo of his B-24 Liberator's crew with his medals. It's difficult for me to take a photo because the glass is very reflective (I'll add it later after I take a passable photo) but there's a "caption" on the bottom (more like a serial or locator number) that reads
"489bg-4g-50:1-3:18-crew #26 845thsq"

I figure that "489bg" and "845thsq" are self evident, as is "crew" (it's a photo of the crew) but all of the other stuff is unintelligible. I don't thing "4g" refers to cellphones, for example. Grandpa never talked much about his time in the war, but he got a Purple Heart, DFC and a USAAF Air Medal with 3 bronze oak leaves. I've always wondered if he was in a bomber that had a "name" or if any decals for it had been made, but aside from one anecdote ("Tail why are you wasting ammo on that German? He's way out of range!" "Yessir, and I aim to keep him there!") he never talked about his time in the air either. I'm grasping at straws trying to find out the name of the plane he flew, so I'm hoping that "locator caption" might point me in the right direction.

Anybody have any idea?

Very interesting, Wes @avispa93
Let's hope you will be able to find the meaning of these codes, searching the internet might indeed be the best approach.
A great anecdote from your granddad.

Here's the photo in question. The caption is at the bottom. You can clearly see that this is a B-24 and it's most likely in the olive drab scheme, but whether it's D-E or H-J is unclear. If you peer into the left-side background, you can see the back end of another Liberator, which, again, doesn't help much. Behind that Liberator almost looks like a geographic feature like a hill or a mountain but it could also be a flaw in the image. I can't get a better photo because it's fastened inside a frame that's sealed inside a display case.

My search thus far indicates that his plane was most likely an H model, either block 15 or 20, but I wouldn't know if it was a Ford, Consolidated, or Douglas-built airframe.

1 attached image. Click to enlarge.

Try the Mighty 8th Air Force Museum in Georgia. They have an extensive collection of specific BG and even individual aircraft histories. It's an incredible museum with amazing historic resources. If they cant help you, likely no one can.

Some promising news, my friend @avispa93!

And at last, the thrilling conclusion!

the National Archives replied and indicated that those records were technical reports related to the performance of H2X radar and had no mention of crews. They then directed me to the National Air and Space Museum for access to their microfilm copy of the USAAF's Aircraft History and Record Cards. That inquiry resulted with the following results

• the Aircraft History and Record Cards were tracking data solely for aircraft operated within the United States, they did not cover any period when the aircraft were being ferried to Europe or their disposition there.
• Personnel were permanently assigned to crews, but crews could be (and were) arbitrarily assigned to whatever aircraft were available as the missions required.
• Aircraft typically had a primary crew and any naming or nose art were applied by this primary crew. If the crews were referred to at all they were almost always referred to as [Pilot In Command]'s Crew (Lt. Smith's Crew, eg).
  -The NASM provided the squadron code (T4) and the unit identifier (Green vertical stabilizer with vertical white band and aircraft letter)

Shortly thereafter, I received a reply from the Air Force Historical Research Agency, which consisted of a handful of documents that included my grandpa's travel orders, assignments and lists of medal recipients. And there he was, his name mostly faded away from a combination of light typewriter keystrokes and non-archival ink, but it was quite clear: his travel orders for the rest of his crew from the US to England, and the aircraft was...

42-94948

He obviously didn't stick with this aircraft for the duration; when 948 was interned in Sweden in August 1944, it carried a completely different crew. B24bestweb has three photos of this aircraft, and I believe these are the only ones that exist. It doesn't seem to have born a name, but it does carry (what looks like) a pinup on the starboard side of the nose. It is VERY similar in shape to the noseart on the P-47D "In The Mood" which was also based at Halesworth (see the attached image from the great Tolga Ulgur: https://imodeler.com/2022/12/1-32-trumpeter-p-47d-1-in-the-mood/) . It also sported applique arrmor plating under the pilot and copilot's windows, and its outer nacelle rings were unpainted metal. Its inner cowl flaps were also unpainted metal.

The End!

4 attached images. Click to enlarge.

Really amazing that this info emerged, my friend @avispa93!