Well, years ago I used to buy nice antler material on Ebay for my knapped blades. I have not done any hand knapping for at least 6 years now.
I remember one set going for $800. and (I am straining my memory) but, I don't think they were nearly as nice as yours. I just checked Ebay completed auctions and one set just sold for $230. but, the seller had unlocked them in order to free them from the skulls. A huge boo-boo on his part. You might want to call around to some higher end taxidermy shops and E-mail them a photo.