Hello!
Having built a late Cobra myself I know this is a tricky subject (here’s how mine turned out:
)
They modified some existing choppers, some were built from scratch, they had three phases of that modification, confusing designations - F being later than G, AH-1S phase III looking exactly like AH-1F - so it takes a lot of research and good references to get it right.
I think you did very well, so congratulations on a completed model and thanks for sharing, have a nice day
Paweł