Personally I would not sell anything that I had "repaired" in the kiln. I would rather be sure than sorry!!
Ian
This raises an interesting question. How do you ensure that the piece - any piece, including new - is "safe" or robust enough to be sold? What checks do people make on the "saleability" of their pieces. What do people do to test the fitness for purpose of their work? In short - how do you know the piece is ok?