Several listed on eBay, from ink-stamped later production to originals - don't get me wrong, I would always rather have original GM over repops (any day of the week), but in light of the fact I don't want to spend $600 on a pulley when I can get a decent repro of one, good price, I'll bite until I can find an original.
The 2 pics attached - one that I pirated from Parts Place, the other is a current eBay listing at $599.00. I saw Pacecar Jeff's listings on there as well. I would rather have the stamped versions as closer to the originals than the ink-stamped ones myself. Note the stamping on the repop is pretty close in font and position to the pic of an original, with the original added "P" stamp at 120 degrees. (at least I belive it's an original - one never knows !)
The disclaimer - this is always my own opinion - everyone has a different one -