Okay, here are some follow-up pics. The first one shows a comparison between the earlier Fujimi 1:48 scale AH-1G (still in the bag here) and the newer AH-1S, also by Fujimi. Most of the parts in this -S model are shared by the Fujimi AH-1J Sea Cobra. Testors later sold the Fujimi -S in their own packaging, but I'm not sure about the Sea Cobra.
You can see by examining the bare fuselages that the earlier -G model just doesn't compare, especially by today's standards. The shape is all wrong, and it even appears to be undersized. By virtue of the fact that the two later Fujimi kits share many major components, combining the two variants would yield a decent AH-1G with a minimum of cutting and grafting, leaving the cockpit as the major obstacle. The Monogram Tow Cobra could be called upon here to relinquish its interior for a good cause!
The second photo shows a few boxes of Cobra kits; whether they are still available is questionable. The 1:72 scale Cobras shown here are the old Monogram kit, which I like VERY much, and the Matchbox kit, which I cannot comment on, as I have never opened the box. I have heard that it's a good kit, FWIW.
The Monogram Cobra has the tail rotor on the left side, which represents an earlier aircraft; be sure to check your reference photos carefully here! The Matchbox kit has the tail rotor on the right side of the tail boom, as has been standard practice since the changeover in the late 1960's. Incidentally, Fujimi/Testors has/had a 1:72 scale series similar to the 1:48 Cobras in that the variants shared common parts, i.e. main fuselage, rotors, skids, etc. The main differences in these kits, both in 1:48 and 1:72 scales is in the doghouses and the canopies.
HTH...
FITTER out (edited to correct a minor typo)