Right now it doesn't make sense to limit yourself to just one rollmark. Widen the field to have a better chance of stumbling across something acceptable. Most stripped lowers are built well and will do the job.
Have you checked all the normal shops in the Treasure Valley? Sawtac, Hawktech, Impact, etc? Just grasping at straws, probably all gone...
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek