Bill, I know a little about the tag numbers. I'd love to know what they all mean, but don't know exactly whom to contact. LS&Co is out, some of their staff can't add 1 plus 1. Lynn Downey there is the vintage person, so I think she is rather busy, but I perhaps will ask her.
501-0000: STF
501-0115: rinsed indigo
501-0134: light stonewash
501-0193: medium stonewash
501-0194: dark stonewash
So these are colour codes, and the only ones I'm interested in. It's not to hard to find out the codes for black or other coloured 501s, just surf on ebay, some include the codes in the item description. Other styles, let's say the 505, does have different codes as far as I know, so med. stone isn't 0193. Older (vintage) 501s were 0117 for STF. I'm not sure about the years, my knowledge is more in the 80ies/90ies. For rigid, sanforized jeans as the 505 and 517, 0217 was used, the rinsed ones has 0216. Same for jackets.
Production date is always a four digit number. There may be other four digit #s, but often you just have to use common sense, the last to numbers are almost always 9something (90ies) or 0something (from 2000 upwards).
The waist button has a number. This number has to be the same as one on the tag or the jeans aren't real Levi's. At least that is what I learned in the 90ies. Nowadays, the button # isn't any more printed on the tags, LS&Co told me that this has no more meaning. 555 would have been produced at Valencia Street in San Francisco. Numbers starting with 5 are U.S. produced jeans, the European ones are 200 and something. Vintage jeans have different stampings on buttons, though.
So Bill, the pair you mentioned has to be a rinsed indigo 501 from May 1993. The six buttons are a bit weird. One too much...I don't know. The (R)-only red tab happens from time to time, they apparently do it for protecting their copyrights, I still don't know how this works, I am convinced these tags correlate somehow with the production numbers on the tag. I got a pair from ebay yesterday with this tag, seems that they haunt me in recent months, lol.