Hi Team,
the 7B5716 "O" Ring is given as :- 8.625" inside diameter, and 0.187" cross section (diameter) and is black material.
Neil,
I see no reason that it could not be fitted to earlier units as in fact the last paragraph of the air cleaner article states just that they can be retrofitted to current and non-current units of the same approximate sizes or, in words to that effect.
Cheers,
Eddie B.