I think that there is an aircraft type in the first edition which was confirmed as being ‘imagined’after publication and so doesn’t appear in the reprint.
The main issue with Putnams reprints is the paper quality tends not to be so good and the copy is taken from an earlier print, and not from original prints, so the picture quality suffers.
Bargains can be had but, like so many thinks, it is a combination of perserverance and luck.