I don't care what vintage or how collectible a guitar is. If the knobs were epoxied to the pot shafts I would put some reasonable effort into trying to crack the knob off and then tell the customer that the knobs and pots were going to need replacement. Then I would destroy the knobs rather than spend "a full day" saving them (without even knowing if it was going to take longer). If the customer bought the guitar then they could take it up with the seller. If they, themselves did the epoxy work then it's just come uppins. You could probably buy actual vintage pot and knob pulls for the cost of a days labor and save yourself the effort.
Glad you managed it though because you clearly wanted to keep this instrument original very badly.
EDIT: Can we assume that the "pickup swap" did not devalue the vintage originality of the instrument? I'm just wondering how much value was preserved by the extra effort on the knobs.?.