I'm at least 90 percent sure that the German and American kits come from the same molds. Any disparity in the parts counts probably resulted from somebody miscounting - not terribly surprising, given how many parts are in that kit.
I've read quite a few complaints in the last couple of years about Revell Constitutions made of cheap, rubbery plastic with lots of flash, warpage, etc. I think the complaints about the German one have been more frequent, but I suspect the American one has more than its share of problems. This is, after all, a 40-year-old kit, and Revell does not have a good reputation for quality control.
If I were in the market for one of these kits, my first step, frankly, would be to check e-bay for a bargain price on an older one. Failing that, I'd probably buy the cheapest new one I could find - and hope for the best.
Caveat: I haven't actually looked at the contents of one of those boxes for quite a few years. I imagine some Forum members who've bought the kits recently will have some relevant comments.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.