Difference between ATTINY's

-SSU has a dot, -SSH has the notch, regardless of the other markings. That's the only thing I can find that reliably matches up with the dot/notch marks.

I have a tiny13V I could never get to even take a flash, don’t know it it was a dot or notch.

Those are just date codes… week 50 of 2013 and week 9 of 2014.

Ah, OK. Any idea on why each processor although supposedly identical, have different markings for pin 1?

Probably to identify the factory that packaged it.