Another Oil Leak (Possibly rear main seal)

[nwo]

I just discovered last fall after over 3 years of having my 1982 Fiat Spider (Also having done a full strip down and paint too) I found a leak near the rear of the engine. Up on jack stands my mechanic (AKA as my Brother-in-law) says it is the rear main seal. I am hoping it is something else. We will have a better look at it in a week or so when we put my new tires on and get it up on his hoist at the shop.. I guess I need to know a couple of things..
1) Is a rear main seal leak common? How would we know for sure? what am I looking for? Not that i dont trust my mechanic, but I know oil leaks can be tricky..
2) If it is the rear main seal besides buying a clutch kit what else should I replace? ( I have noticed the clutch pedal getting bit higher since the leak started, but this could be in my head as I don't drive it frequently)
3)Tips on the job required. He did work at a Fiat shop for a year but any tips are ALWAYS welcome!!

Thanks so much for anyones help or input!!
Rob.

[So Cal Mark]

make sure the crankcase ventilation system is working or you may find the new seal leaking shortly after replacement. With the clutch kit make sure you get a pilot bearing. Other than driveline parts, there really isn't anything else to replace while the tranny is out