I should've asked if yours were from the "original" company. That notwithstanding, from a post by Peter Gransee on CPF:

"My new patron has agreed to provide limited service on lights my now defunct company had made. If the service requires a replacement of a part and the part is for a light we don't make, we don't have the part. In that case, we can offer people a store credit. I hope people can see that this is a very very generous offer on the part of my employers.

Send me an email please peter@arcflashlight.com (to initiate service)."

Since the "new" ARC still makes the AAA version, I would think your odds of a repair/them having a part are fairly good. Granted, there was a version change at some point, but I was under the impression changes, other than upgrading to the newer/brighter Nichia LED, were mostly cosmetic, e.g. slight taper to the head and stainless steel battery contacts. Certainly nothing to lose by sending him an inquiry.

Good luck!