Found on Toolarmy regarding the signed Lateralus Vinyl:
They are not individually numbered. I believe that they are factory sealed, so my advice would be to get a re-sealable protective cover if you open it (and I’m sure many will open the album – those whose intent isn’t to put it on ebay). Each copy is individually signed by all four band members (one per side on the ‘slicks’ (the special process I mentioned earlier). The number of copies is between 250 – 300. I’m not sure about any other distinguishing features as I didn’t really examine any of the signed copies that closely (and I don’t have one). I know that Adam put various little drawings in silver ink along with his signature ON THE SIGNED COPIES OF SALIVAL, but I don’t think he did this on the vinyl. His signature, itself, is artwork, though (have you seen it?). Hope you enjoy your copy.