No, I know your source for this and he is not correct.
The Hasseblad cameras were modified to eliminate some of the shutter speeds (including bulb), but the surface photography used 1/125 and 1/250 second routinely. There was a paddle to switch between them. Three f-stops were routinely used: f/5.6, f/8, and f/11. Again, a paddle to switch between them.
The problem with Allen's claim is that Ektachrome has a notoriously narrow exposure latitude. If you're going to bracket, you need to bracket by half-stops. But the Zeiss Biogon lens did not offer fractional stops, nor would it have been especially easy to adjust them in space gloves. The conspiracy theorists—including Allen—tell us how impossible it would have been to operate cameras wearing space suit gloves. Then they turn around and try to tell us they should have been doing all these fine-adjustment operations to ensure good exposure.
As usual, Marcus Allen doesn't know what he's talking about. Consequently @Vixen—who continues to rely on him even knowing that he was a liar and an ignoramus—is also wrong.
Thanks for the correction. I defer to your obvious expertise in the subject (See Vixen, that is how it is done).