Yes Stu, I think the mudguards of any Ducati with a Showa equiped front end are interchangeable (except for the newer 999 and Multistrada types).
If the SS has the same fitment as the 748/996 etc then so does the ST2, I know that because I got a Casoli carbon guard originally fitted to a 996 from ebay for my ST, and although I haven't fitted it yet the hole positions are identical.
If I didn't want to keep my original guard you could've had it, but ST2/4 mudguards crop up on ebay quite regularly