Call me crazy, but I'm guessing that's Dodge... They used the "Knight" logo and the spread wings, in varying designs, over the years.
I would imagine anyone restoring or owning a stock Lasalle of that era, would love to have that. But, as many will tell you; Sometimes it's harder to find a buyer, when you have a rare item, then it is to find a rare item, when you're looking to buy. There was a member trying to sell a Stutz Bearcat water pump, in the classifieds, for a while. Very rare part, but very limited buyers.
You COULD get on the AACA forums and sell it there. Those are the guys who have the need. http://forums.aaca.org/forum/46-cadillac-lasalle/