Yes, Proboscidea parviflora var. hohokamiana produces white seed. All Proboscidea species produce very similar looking seed pods though.
As far as I know:
-Ibicella produces only black seed.
-Proboscidea parviflora var. hohokamiana may be the only Proboscidea variety that produces white seed.
-The other major Proboscidea species such as louisianica, althaeifolia, and the typical parviflora produce black seed.
So.... based on the claw in your picture, I'd say you have Proboscidea species that (obviously) produces black seed. You'll have to wait until your plants flowers to determine the species. The flower color will give it away. However, I have heard that they all readily hybridize. So, there is a chance you may have a hybrid.
Good luck growing them!
Oh, and here is a list in case you need it:
-Proboscidea althaeifolia = Yellow flowers = Black Seed
-Proboscidea louisianica = White flowers (may have spotted pattern) = Black Seed
-Proboscidea parviflora = Light pink flowers (may be whitish) with a yellow "nectar trail" = Black Seed
-Proboscidea parviflora var. hohokamiana = Pink flowers with a yellow "nectar trail" = White to Cream Colored Seed