Let's break this down. From 1970-1972 their was no bird on the hood, only a small nose bird. 1973 was the first year of the Hood bird and it was an option. So you could order a Trans Am without a hood bird and you would get the small nose bird. So as far as accuaracy is concerned JL has been pretty much right on, with exception to no TRANS AM lettering.
Hope this clears it up a little bit, for the early second gens. IF you ordered a later 2nd gen without the bird you didn't get a nose bird. Not sure when they stopped doing that, but my guess would be 1975.
JK, I was wondering what that casting was, but I was unsure. Thanks for the clarification. I sense a drifter series coming on. Nice to see the diverse castings for the Import series.