Yep, early second contract LanCay... still a very nice bayonet. I have a couple of these.
Hard to say what they are worth. I have two that are in new condition (15yr old or so) that I picked up for $60ish, but have seen the same ones with a hollow ground blade go for $250.
http://www.popernack.com/shop/shop.php?aID=20&xID=1429