Ahhhh, is the reason for wanting only "New" cards, because you're afraid the card will be defective?
As a helpful data point, it's very rare with Mellanox cards. As in, I've not yet seen a defective one, though I've personally only handled ~30.
People occasionally send me "defective" ones, but they've all been fixable by flashing with new firmware (then sending back unfortunately. doh!).
If I was doing the buying, I'd look for a used one as they're much cheaper. Mellanox cards work well with Linux too.
A cheaper dual port: