So was it stamped or not?
It was stamped .358 Winchester (see post no. 1), a factual apparent anomaly which prompted me to start this thread. Unfortunately, I can't recall which model number (Model 88 or Model 100) was stamped on the barrel. It looked to be an authenic Winchester stamping and, at the time, I just assumed it was a barrel originally made for a Model 100. I wish now that I'd paid better attention-not that knowing that (the model number) would have necessarily solved the "mystery" for certain; but it certainly would have helped.