I actually bought two mats from Jim Carter for the 45 GMC. The first one was perfect too but when I cut it I mis-measured and ran it in the truck for about a year before the mis-measured cut bothered me into replacing it with another. Again, both great quality.
I also bought one from Carter's for my 52 GMC that I owned prior to the 45 GMC and also one for my 51 GMC prior to the 52 GMC. All first class quality.
Never seen a rubber floor mat turn to dust. Would like to see some photos of that.......