Most people only know one design of — the Which I think would be a problem if you bought this dress (from thefrock.com, $1500, click on the image to check it out, but you'll have to scroll down). Because they would ask you "where'd you get that amazing dress?" And you'd say, "It's a Rudi Gernreich," and then (inevitably) they'd say "Oh, the topless swimsuit guy?" and where does the conversation go from there? (It goes to "Excuse me, I HAVE to catch that guy by the bar," that's where it goes.)
So I say, if you buy the dress, just lie. Say "this old thing? I've had it for so long I've forgotten." Tell them your grandma made it. Tell them it was on sale at Nordstrom Rack. It's just easier that way. And it's still great without the name. Possibly even better.