When we got our airworthiness certificate, it was on pink paper and titled "Special Airworthiness Certificate" I think the "Special" is supposed to apply to the RV-12s that are bought ready-to-fly, not built as a kit. I checked with another RV-12 owner/builder, and his was issued a "Special Airworthiness Certificate" also. The problem is that the rules seem to say that to work on a "Special" you must have a light-sport repairman with a maintenance rating, but on an Experimental light-sport airworthiness certificated aircraft, the inspection may be done by a light-sport repairman with an inspection rating.