Can you post some pictures? There are many ways to do cowl pins, so advice would be a shot in the dark without knowing what you have.
Of course, the best resource would be the guy you bought it from (or who built it) - can you ask them? I'd think that they'd be happy to show you the motor if you bought the airplane! One of the things that is being looked at right now in the Safety world by the EAA and others is the higher-than-normal accident rate in homebuilts that are BOUGHT, rather than built. Many of these accidents are being attributed to variations in airplanes from the initial design, and the lack of a "checkout of the new pilot/owner by the old pilot/owner.
I am not saying that cowl pins are going to bring you down (I am pretty sure they won't), but if the previous owner didn't show you how to get the cowl off, what other little "improvements" might he not have shown you? Worst case? Think John Denver and his odd fuel selector.
Sorry for the pedantics, hope I don't offend,
Paul