Centurion Elite RS components
 

I just bought a very clean Centurion Elite RS, with the "Miami Vice" paint scheme, off of Craig's List.

The RD is a Shimano 105, which I'm pretty sure was not offered on these bikes at the time. I'm having trouble finding a good reference for the original components used on this ~30 year old bike, so I wondered if anyone knew whether some came with 105 parts? The crankset is Shimano 600, and everything else appears to be original, but the RD is throwing me off.

The only years that the Elite RS was Shimano equipped were 1985-1986. Shimano New 600EX was spec'd for both years but the 1985 version was friction shifting, while the 1986 version had indexed shifting. The 105 rear derailleur is an obvious replacement. The Elite RS was discontinued at the end of 1986.

Thanks, T-Mar.