Inner Clutch Cover Seal troubles

Hi everyone. I’m new here. I’ve had a few of these old 2 strokers over the years, and decided to get another one recently.

When I pulled the engine for a rebuild I noticed, after the head work was done of course, that my inner clutch cover seal was mangled. Bought a parts bike, same problem.

I can’t buy the seal anywhere, as it is discontinued. I’ve found lots of seals on Ebay for 93+ Trail Bosses but nothing for my 1990 4×4.

Can the newer seals, or a seal from a different Polaris be modded to fit? Is there any other clutch covers that can fit this bike, and still be able to buy seals?

Thanks!