My (used) copy of ...Gold Rush has those letters on the label itself (the sticker in the centre of the record (RS6383 31,009 RE2), but in the dead wax it has etched the same thing but instead of the 'RE2' part, it has '1A'. I'm guessing this is the same as what you mean, but am slightly curious. No matter, it sounds excellent.
To the OP, you won't have trouble these days finding great vinyl as others have mentioned, but two that stick out as essentials are My Bloody Valentine's Loveless and the 4 Men With Beards reissue of Television's Marquee Moon. I'm sure there are loads more, but you're honestly better off with music you know you like. You won't have trouble finding stuff.
Edit to say that although I haven't heard any digital hi-rez versions of Rumours but I did have the good fortune of finding mint copies of Fleetwood Mac's big three albums a while ago, and they sound great. Cost maybe $13 for all three. I could tell whoever had them before treated them well b/c they all came in aftermarket non-abrasive sleeves.... one of the actually had this thing that had 'Realistic Anti-Static Sleeve' printed on it... it's still in there, and the thing looks just like a giant Zip-lock sandwich bag. That was quite the used vinyl haul that day, I found other great stuff too. I think I may have to go by that store today.