True ISDT used bikes had the rider number engraved into the paint marking I believe. If a bike was used for the qualifier series, they just applied the paint. I think they still used that practice in '77. If used for the ISDT, it should have holes drilled in the head and cylinder fins for a lead seal to be installed at that point to seal the head to the cylinder, also.
Type at you later,
Dan McEntee
Type at you later,
Dan McEntee