Looking at archive.org, there's nothing but a "contact us / patent pending" text-only web page that exists of the hypothetical MtG trading card site. Also, the Wikipedia assertion appears to have been copied from Wired, potentially a seed for citogenesis[1], as Wired is the one and only source of this claim and we have no supporting evidence.
We cannot know what was reused from what, absent new evidence, as there is no public example of an actual MtG trading card site that I can find anywhere, just a quick note saying that the idea was "patent pending" and that one might someday be found there until a Bitcoin exchange popped up.
I would be quite interested if anyone has new evidence. The record, so far, is a bit thin. Perhaps the Jed McCaleb has a Github or other public repository containing items of interest?