Inspect the tire thoroughly before having them mounted.
I've swapped tires, borrowed R-comps, and flat out bought used tires and take offs for the car and moto in the past without any issues. Shouldn't be a problem for you as long as you are confident the tires are in decent shape.
Edit: Didn't know this was in the regional forum, that's what happens when I blindly browse newsgroups.
I do not have any specific experience with A&K used tires, but the above is my overall experience with used tires in general.