Since they used lower case 's' and didn't specify, no it doesn't count.
Furthermore it still doesn't address the issue of this being an ability that taketh away not an ability that giveth.
Finally I ask yet again, why? most if not all defensive items don't stack with VoP benefits anyway. I mean between the defensive boosts, the offensive increases, and the ability increases, about the only items that still apply are the inherent bonus books, skill boosters, feat items and spell storage. All of which would violate the 'can't own expensive stuff' part of the vow even if carrying and using them weren't prohibited.
There's two aspects to that vow remember.