I recently purchased two sets of US Navy numbers in 1/48 scale on EBay. I posted pictures of them on my Hellcat build thread, so you can look and see if this is what you’re after.
382075082103 is the item number for the smaller 8” and 12” numbers.
131449131299 is the item number for the larger 18”, 24” and 36” letters.
I have no affiliation in any way with the seller or the items listed for sale there. Please check out the photos of the decals and decide for yourself.
Hope this helps you.