the letter R stamped under each barrel indicates the gun was re proofed when the chambers were altered, according to a site i was on, that mark was used in london and birmingham, to indicate a repair had been doen and reproofing taken place, or that the gun was altered in some way that it required re proofing, its a wonderful little gun, im happy with it, now to finish my collection i need an american made sxs, of gd quality, parker, Fox, lc smith,, i have 2 remington 94ès, which i also dearly enjoy shooting, im located in nova scotia canada, i would trade a very valuable rifle i have for a shotgun in this list, of the equal value, i prefer them with damascus or twist barrels, just something alluring about them when you look at them