Ah, I think I see the issue. And no, the change shouldn't be blocked behind any feature locks.
The check for the arms should have checked if you don't already have human of bovine arms (or if so, that they are not furred). There should have been another check for if you have furred human arms (since you'll need those first and they'll convert to bovine shaped ones). The additional check should hopefully be in for the next release.