I'm not sure tuskless from anywhere are importable - anywhere.
It has nothing to do with the ban on ivory or elephant that the US implemented recently in respect of some countries, but rather has to do with CITES.
All elephant in Southern Africa are Appendix II, which means you need an export permit to take any part of the elephant out of the country where it was taken. And you can't get the export permit without a CITES quota allocation. It is my understanding that CITES will only issue quotas for trophy elephant. As a result, if you shoot any non-trophy elephant anywhere, you cannot get quota, and therefore cannot export. And that applies to any part of the animal, up to and including hair bracelets. So in this case, it really isn't a USFWS issue, but a CITES issue.
I could be wrong, but that's my understanding of how CITES works.