I would say none of the above. Others will hopefully chime in. I believe they do not have a washer. Would be black oxide. 6 point head. Unsure if it had the "Highland" marking or a TR marking .
Yupper, I agree, no washers on any of mine. Anyone I had though were a few years old but still had the factory intake on them, so I can’t see anyone just changing bolts. Kim
