Is there a particular movement you have questions on? The older hand-wind reps for the most part used a decorated 6497 and the automatics used a decorated 7750. There have been some variants, but those are your two main ones. The new movements are mostly the same, but with more decorative plates to replicate the genuine articles, i.e. not new movements per se. The P.3000, P.5000 & P.9000 are the main "new" movement decorations, but I believe they still use the 6497 or 7750 as a base underneath the plates. There are numerous threads on here dealing with movement takedowns -- my advice is to nail down which specific movement you are interested in and search from there.