which is the top ring? 350x

[kb200x]

I just got new rings they are stock std. bore part # 13001-ha5-305 and i can't figure out which is the top ring both have an R stamped on them. one is black the other is more of a grey color. I can't see any bevel's cut in either ring? Which goes on top? The darker black colored ring is ever so slightly larger ?:wondering

Help!

[SWIGIN]

normaly the top ring has a chrome face on the edge that touches the sleeve.

[MTS]

Chrom/gray one on top....letters/numbers facing up.