Uhhhh.yup. 100%. My gen caseback set me back several hundred dollars. Gen crown and tube, gen T-19...ugh.. Gen Rolex Cal.1520 mvmt, serviced and rebuilt using gen parts...ugh... I mean it's a great watch and all, and the last piece of the puzzle is a really bad-ass insert, but those are super expensive. Seeing what the MillerDave has avaiable.. I suppose my freak of a 5513 is probably as gen-close as you'd get, but it's still not perfect. The dial lettering, while perfect, is flat and kind of depressing.
I would also say it depends on what you're building or want it to look like. Not to hijack - but here's mine - this watch if sold as genuine would fetch about $14,000 to $16,000 right now. (I have box & papers too) so having spent like $3500 bucks to build it isn't too bad considering it's almost all genuine.