As long as the inside part of the head gasket is on the sealing surface of the block it should be fine. You could check to see if you can get a very early honda head gasket but I doubt you will find one. Shortly after the 70 model year honda added the extra bolt there to help stop oil seeps. Aftermarket wont make a gasket for a one model year so they make the later gasket. If you want you could add a dab of hondabond on there for some insurance.