Yeah, what
@itronin says. Its certainly possible that there's a supply of "new" cards that were sitting in a warehouse unsold for a long time...but probably not as likely as counterfeit or something else questionable (like that its actually used but cleaned up well). Not that used is bad, these things last pretty well. But, if it is used, $52.88 is pretty darn pricy unless you're getting some sort of added value, like having already been updated to the newest firmware ahead of time for you and guarantees to be genuine.
The card in the Ebay listing has an IBM (Lenovo) spare part sticker on it (closest to the bracket) , The part number, FRU 46C8937, is the spare part code and 46M0912 (not present on this card, but helpful for looking it up on Lenovo's website) is the code for it as a stand alone Option kit.
Lenovo's product page has a picture and there's some differences from the Ebay listing. The heatsink is different (full length fins vs pins) and the jumper for an IBM Advance Raid Key is on the picture on the Lenovo site (above the heatsink in the picture), but is missing on the one in the Ebay listing. Kind of fishy, but then again I'm no expert on these. So, it could just be a variance or different production run.
6 Gb Performance Optimized HBA (Withdrawn) Product Guide (withdrawn product) > Lenovo Press
From what I read, the chances of a counterfeit are lower with OEM branded parts, but I understand there are still some out there.