Yes other years will fit with some exceptions....
First of, w/ a S you'll need the center radiator cut out so you'll be fine w/ any S Boxster cover up to '04 (you could go non-S and just cut it yourself if need be). You'll also be ok w/ any 996 cover up to '02 (where they changed it for the 'fried egg' headlights). On base 996s I think you'll need to cut the black cover over the 3rd radiator but at least it has the opening in the painted portion of the cover. Plus there are lots of aftermarket options. Sorry to hear about your misfortune but good luck....
PS - FYI - there is a current bumper thread over in the Show & Tell Gallery -
here