1979 master cylinder flat ring part number

Hello all. I'm rebuilding and painting my 1979 kz1000 front master cylinder. It is currently fully disassembled for prime and paint. The parts diagram does NOT show that the removal of 2 screws inside the plastic reservoir will allow you to remove it from the aluminum housing. Under the plastic is a well that feeds the line.

I need a part number for the EPDM flat ring under the reservoir. The original is not broke just too flat i suspect. If I'm this far in i feel i would rather just replace it. Any help would be much appreciated.

I do not know the part # but this link has them.

www.redlinecycle.com/Brk%20-%20Trap%20Rsrvr%20O-%20Ring.html

I had bought one from him years ago but couldn’t find the actual page and didn’t want to post something I couldn’t be 100% sure of. Thanks for finding that.

Here is a link to a replacement of that O-Ring.
www.kz-1000.net/post/3676028622/kz1000-master-cylinder-rebuild