One thing I learned on my Falcon building journey is to always strive to obtain the vintage or original issues of the donor kits!. There are many kits that have been reissued over the years, but more than likely have been remolded or altered. By buying the vintage or original issues you know you have the exact same kit ILM used, with no surprise of missing parts, altered parts or a completely re-tooled kit!.
I should know...been there...done that!. Quite a few times i have been caught out thinking a newer issue would suffice...nope!.
Tamiya is a good example of a manufacturer altering molds over the years. The box art might look the same, but the contents not so much!.
Just be aware...check sprue scans...ask around...just don't jump on a kit like say the Tamiya 1/35 Tiger 1 newer issue & expect to find the same parts as ILM used back in 1976!.
Stu