Nice to see you starting on these years.
The 73+ bird ran till the 78 model year (unless you had a Solar Gold car in 78, then it had the later style bird).
The one piece TRANS AM decals - I know 76 models still had them, not sure about 77 models....then the font style changed again for 78 to the later style.
The small nose bird - I believe this was only used on the nose for 73 (only) when no hood bird was ordered. Question here is - is this the same decal as used on the rear spoilers of Formulas through the years?