I had a similar issue with my '01 Vette.
It wasn't the actual seal, but the rear timing cover.
While I was there I replaced the "Barbell". That can cause excessive pressure to rear timing cover if I remember correctly. (It's been a few years since I did the work).
During my investigation, I read sometimes the oil pressure sensor leaking could make it look like the rear main. I didn't have that issue and didn't see how that was possible. I suppose if it a minor leak, it could seep down there.
When you go to replace the rear main, replace the entire rear timing cover. The rear main seal is installed in the factory and you don't have to worry about installing it correctly. Plus, it come with all new bolts when buying from GMpartsdirect or one of the other factory parts discounters.
I'm not a fan of the fixes in a can, but it's worth a try if you have no other choice. I used some in a leaking transmission and it worked, but took about 3 months to do so.