I just had a look and they were both 88K disks. So apparently not the case.
Well, as I say, no matter the reason, as long as the contents are there and they work, then it's all good for me.
I can understand you need to verify them for Atarimania. There may be some information available in the threads where Thumpnugget was discussing putting these DVD's together. I doubt he owned and imaged the complete collection himself.
They probably tried to keep them at 88K for 810 drive owners.
Yes, Thumpnugget didn't copy therm from original disks. He just gathered them from the Net.I was working with him when he was scanning all those books and magazines. I even let him borrow a bunch of books so that he could put them through his document feeder. This was before I got mine.