Wiring 67 fastback....

Ok. So I have from batt to starter main post with 1/0 (batt in trunk). Then power goes to 'megafuse' with 6 ga (is that 6/0?) Then to the starter relay with 6 ga. I noticed my starter relay is of later vintage with an extra post. Can I still use the later relay? I probably have an earlier one around here someplace, but this one is in nice condition.

Thanks FABO