Neat to see this coming along Spiros.
One thing I just realized, going by the box top artwork, and looking at the pictures of the airbox assembly, the carb linkage, the decals and the sprues with the sidecovers...They have either a '69 or '70 (K0) pictured on the box, but the plastic & decals they provided you looks like it'd make a '71 (K1). The reason why I say this, the early ('69/'70) had a smooth airbox (OEM being metal painted to match the tank, sidecovers, and headlight fork ears). The later ones ('71 and after) had a ribbed air filter assembly (like the one in your picture) made out of thick plastic that was semi gloss black. The sidecovers are also different that the early ones had four "gills" towards the front (like the box artwork), and were a little larger; the later ones were smooth (except for where the plastic logos bolted onto the side, which in the kit is represented by the "750 four" decals). The '69-'70 versions didn't have much in way of the carb linkage, just 4 cables that ran from a junction barrel, but the '71 and later bikes did (similar to what the kit has). If you'd like I can dig up some pics, but really from a model makers' standpoint, if you're goal was to make a '69 or '70, the big thing would be the side covers (just cut four gills into the sidecovers) and paint the air cleaner assembly to match the tank & sidecovers.
Will be a fantastic model regardless, Spiros. The only reason why I'm typing this much is because of how much I've come to appreciate these bikes!