It looks like John solved it. I doubted that the D&RGW would have an error like that occur. The only number switching appears to have gone on with some of the outfit cars, and I couldn't have imagined that there would be any reason to have switched a 3000 series number.
The car is located on the south end of Alamosa near a junkyard of sorts, just north of Rd 8S. It's on Dave's site as 3104, which is what I told him to put since I thought I must have read the number wrong. There was no lettering on the outside of the car, but the number was in white above both doors, which is a lot easier to read than the black lettering that shows up sometimes.