Crawdad,
If it predates the 1972 Marine Mammal Protection Act (Dec. 21, 1972) and has the proper tags than I believe it is still legal to have, other than that it has to be a handicraft from a native (Eskimo). I don't believe that the new Ivory 'forced law" covers walrus just elephant. It is likely worth north of a few hundred per pound the issue would be if it is tagged after the date and finding a buyer. You can buy fossilized walrus and mammoth but fresh stuff is different. Best to be safe on any of this stuff these days. The days of the government proving what kind of ivory and date are over with the new law. It now resides with us to prove it and or face the law.