Does anyone remember when some discount companies sold "Eastman Movie Film" loaded into 35mm cannisters along with processing into slides along with negatives? I tried that for a bit when I was pretty broke, and I have recently scanning some of those slides. They are fairly rosy looking 42 years later.

Yeah. The dead giveaway is the sprocket holes. On MoPic stock they have a radius to the "short" ends of the holes, still film hole was more rectangular.

Dave, did you look at the sprocket holes?