RE: MVVS .77
C,
The MVVS 12.7 (.77) GFS/R indeed does not have anything to line-up with the notch in the sleeve.
There is no pin in the cylinder casing for that purpose, like in some other engines.
The larger bore 15 cc (.91) has clearance notches in the sleeve's rim, that line-up with the head bolts.
All you have to do during assembly of sleeve, is to line-up the exhaust port, with its counterpart in the cylinder casing.
The exhaust port is the tallest one (top lip closest to the top of the sleeve)
Everything else will be where it should be.