When you say old school A10 pistons, do you mean the earlier ones were different? or just old A10 pistons in general.

I replaced the gasket on my A10 a month or so ago and it is still the original- shim style gasket with material over-lay.....as far as I'm concerned those only came out at factory?

It's a spin out if it was the orgiginal gasket. 40+ plus years without a gasket change, is that a good thing or a bad thing!