I have a GA645 with the 60mm f4. A fine little (for a medium format rig) camera. I do suffer from the forgetting lens cap issue though.
Far as caps and hoods go, unless you're really a stickler for brand matching, just match the filter ring size. Mine is 52mm, and while I do have the original Fuji hood, I'm actually using a Nikon lens cap since it's center-pinch and thus easier to use with the hood than the stock side-pinch Fuji cap.