I don't really think there is a 65 block plate. Just lots of different ones.
You can find them with the cam plug hole cut out also.
This one has 4 holes drilled in it.
I like the ones with the cover over the cam plug. Just in case it might come out the block plate
will stop that.
There was a seal strip along the lower lip of the B plate where the inspection cover mated up.
I believe at first it was a felt type material that was glued on. Then latter on a rubber foam type material.
I think is was for noise suppuration and I guess you could find one if you looked hard enough.
I doubt you will lose points if you make something up.