I guess it is possible that someone bought one of those franklin mint quarters and released it into circulation but that just doesn't make sense.
Sure it makes sense. They bought them and then when they went to sell them they found that no one would pay more than face value for them so they just dumped them. It happens. The Treasurer at one of my local coin clubs went to the babk a few months back to get change for his wife's business and got three solid rolls of gold plated state quarters. (all different states) Someone, might have even been a dealer that bought them for face off some TV buying sucker, had just rolled them up and deposited them.