Hi, Mitch.
The markings should be fairly easy to see on the top face of a new ring, close to the ring ends. Once the ring has been used, ring movement tends to rub out these markings, so you will probably not see them on a used ring. The marking is probably "NPR", standing for "Nippon Piston Ring" who manufactured them. On the cast iron barrelled motors, the oversize will be shown on the opposite ring end as "50" for +0.5mm, "100" for +1.00mm and no number to indicate a standard bore ring. Of course, no such marking will appear on 90 Sport, 175, 200 or 350 rings.
On rings for alloy cylinders (90 Sport, 175, 200 and 350) both rings are identical, so there is no specific "top" or "bottom" ring. Just fir the rings with the marking uppermost. The 50 and 90 iron-barrelled motors had a chrome plated top ring, easy to distinguish on a new ring by its silver colour, where the cast iron bottom ring is black. Not so easy to tell on used ring, as both end up polished and shiny silver!
I think the idea of a "right way up" for rings originated where the ring is not symmetrical. Some have a taper on one face (i.e. they are keystone shaped in cross section) and if one of these is fitted upside down, you won't able able to compress the ring fully in its groove to fit the cylinder.
Cheers,
Graham