Oh, okay, I thought the Z was in line.
I've seen an S neck(with ovals) that went like WALRJ-O, and both my RG7xx necks have WALRJ-T24. The last R neck I saw has the same digits as this one, and one other one from an R540LTD had UALRL-T. I kinda put 2 and 2 togther, since every neck with the teeths has a T, the one with the ovals had an O, and the R's come with smaller frets than the S and RGs.
Now more modern ones have the model number instead from what I've seen... hmm.. lol