I have two Gassers, but Im helping a friend with his CR 125

[FFRDave]

He has leakage around a couple of the cylinder head studs. It also looks like the leakage is along the mating surface too.

We removed the head and applied some machinist dye to the head. After rubbing it on a sheet of #600 sand paper on a flat surface, the blue dye along the outer edge was rubbed off.

This indicates TO ME that the outer surface was raised a little. After the first couple light rubs on the sand paper only the front and rear of the heads mating surface came clean. Upon subsequent "sanding/rubbing" the left and right sides bluing was also removed.

If these 1989 Honda CR 125R heads come from the factory absolutely flat, then this indicates some warpage is present, and continuing this "sanding" process should bring it back to its correct flatness.
If, however, these heads are engineered with a slight taper (to allow the head to flex when torqued (or some other engeneering reason)), then it would be a problem to continue to remove material from this outer edge.

HERES MY QUESTION...
Does anyone know FOR SURE if the 1989 HONDA CR125R head is supposed to be absolutely flat or slightly tapered where it meets the cylinder ?