Platinum RF
Well-known
As far as I know the info is pretty accurate.
But that said..
Maybe its best to do a poll on the exact lens #'s and their coatings.
And try to figure it out from there..if enough people respond..
I think purple was in the 1st 100 lenses.
Amber came in strong in the 400's.
Even spacing came in the 600's.
..
The serial number is randomly assigned, the 500/500 may have the earlier amber or purple coating, the 1/500 (? Hold by Mr. Zhou) may have the latest coating.