i had a type r exhaust cam that had two raised rings near the cam seal. there is a little positioning journal (thingy) near the cam seal, it is raised about an eighth of an inch above the other journals, and about an eighth of an inch wide. right next to the cam seal, with two raised rings on it. i have never seen a b16 or gsr cam that had these raised rings, perhaps this cam was from a US type r? sorry if this is not clear enough, i will be happy to try and rephrase it.

 

http://ff-squad.com/VtecCams.htm

This might help you.