PacParts is a great source for CASIO G-Shock parts, but lately I've been finding a lot of models either not in their catalog, or listed but with no parts attached (and a message to contact PacParts for assistance). There is an alternative I just found, though.
Check out Boley, a German website that is a reference site for many different watch brands, including CASIO. Plug in your model number and search. If it's a valid model, you should see one or more hits appear. Click on a search results entry brings up a parts list. So, you can find out the exact part numbers you need and use this when contacting PacParts and CASIO parts, to help expedite the search.