Hey, di_nate.
You've done some really good work on the 210 so far, so don't get suckered in to eBay goofballs.
Let's clarify one thing right up front: all MBZ modern-generation passenger vehicle chassis -- with the exception of the G-Wagen -- use 5x112 for the hub bolt pattern. Period.
There are some wheel manufacturers who for some models provide a multi-drilled pattern and you can tell by looking at the wheel, because there are more than 5 drilled spots for the bolts to go through (typically the manufacturer supplies a cap or cover of some kind either for all of the bolt holes or the unused ones). Personally I don't like these one-size-fits-Europe designs but it's probably a matter of personal taste, not safety, etc. I suppose you could also argue it makes them marginally lighter with all of those extra holes.
That said, if you trust the eBay seller, you confirm fit/pattern/offset etc. through e-mails (so you have something in writing) and they are quality wheels, that may not be a bad way to go.
Good luck and enjoy the continuing mods,
Greg