CX650C engine and serial numbers don't match-RC11 and RC12

[Toadman]

I just got a cx 650 c for $200 with just a few repairs needed to make it run (melted plastic connector on rectifier, and plugged fuel screen). I have been looking around the internet to learn more about this model. I found some sites that say if your frame number has RC11 so should your engine. My engine is an RC12. Has the engine been changed? And if I order parts, is there any difference I need to know about?

[kirbb9]

My Honda ID guide sez
Frame (83 cx650c is JH2RC1105DMxxxxxx
Eng is RC11E-2xxxxxx
I didn't see an RC12 listed, however all years of both cx and
gl 500 and 650's do have the same codes on both the frame
and engine.

Brady