I don't think 1200 XLH parts would be too hard to find. The 883 model, since there were fewer made, might be more of a challenge for the 883 specific parts. No self respecting biker would ride an 883 anyway.

Parts for Harley-Davidson Sportster | Exhaust | Seats | J&P Cycles

The 1200 came out in 1988. Some info http://www.autoevolution.com/moto/harley-davidson/sportster-1/