RealOEM.com site is a parts microfiche resource.
If you enter your bike vin into the relevant box, it will tell you the model type ie 1200 or 1250, (something you have not added here to help us help you) and provide a parts browser to look at the bits fitted to your bike. If a 1250, which I’m guessing as you specify circlip rather than R clip, it will be fitted with Hayes calipers. It looks as though the relevant parts come as a set described thus: Set of mounting parts, brake pads 34118405105. The set includes the sliding pins in addition to the circlips. If it was me who was searching for a replacement, I would visit my local dealership and ask availability or a local motor factors who likely have them in a range of sizes. There are two per caliper so take one of the other three along to compare for size. Buy a slack handful in case of further losses.
Alan R