PROE DOES NOT CONTAIN LIBRARY OF STANDARD PARTS. It is very easy to create them thru family tables. You can also click on 3dmodels at the TOP OF THIS PAGE.
Best Hardware Lib I have found is in the online catalog at McMaster Carr..... Not only are the files generaly solid (as in no "gaps" in the iges files but you get part numbers to order by and costing all at the same time. If you haven't visited their web site..... caeck it out!