Semantics aside, they take into consideration the larger bore when they build the various piston models. It's the piston design and final assembly, not bore size, that gives you final comp ratio. If you aren't measuring squish, you are just guessing. Now if you simply bored the cylinder and rebuilt it with a oem flat top piston and the exact same brand of gaskets, you will increase comp ratio, but it should be relative to the increase in displacement, 1.039%. Not worth it in my opinion.
I found one website from Europe that listed the Raptor 660 and SZR 660 as compatible with the rod they were selling. That probably isn't any comfort for you but it may be more of an answer than you will get around here with Bill gone and the lack of activity by all of the other MZ Skorpion specialists that have graced this forum in the past. Try emailing them. http://www.sandifordracing.co.uk/prox-c ... 7171-p.asp