I went through all the extra calipers I have recently. I wish I would have done so over the years as I acquired them because pretty much all the pistons were shot now from sitting all that time full of bad (waterlogged) brake fluid. The pads were hit and miss. Some I could tell were good from just looking at them. Others were oil soaked. I bead blast them and that shows me if they are still good. Oil soaked ones are dark colored of course, but the blasting turns them a nice light brown again. If they're good, they'll stay that way. If not, within an hour or two, more oil will ooze out of them and turn them dark again. You could try blasting yours and see if they stay light brown or turn dark again.
I quite like stock pads. I put aftermarket pads on my '78, Ferodo Platinums from 650Central I think, and wasn't real impressed with them at first. But now they seem to work pretty good. They have about 5K miles on them and maybe they just require a longer bed-in period than others, or maybe the 11mm MC I swapped on is helping. I still have stock pads on my '83 but it doesn't seem to brake quite as well as I remember my '78 doing while it still had stock pads. At this very moment, I'm in the midst of swapping a 1/2" MC onto it so we'll see what that does.