I HAVE one that I got as part of a collection. There is no "two versions" that I know of. I've heard some got stampped wrong and the circular "m" was printed half-on-the-black, but I've never seen it.
According to the M tG, Odds & Ends (v1.07) file, "one has the prerelease date stamp right next to the cards type and the otherone has the stamp aside the copyright line," the later one being the rarer one.
Also, Cutting-Edge Collectibles lists two different ones for sale. I tried emailing them for a scan, but it's not in their policy to give out scans.
Anyhow, did the Dirtcrowl Wurm promo actually have a circular "m" on it? The only ones I have seen are from bad scans, so I can't really tell...
