Having just invested in a K1, I thought it time to get my Sigma 35mm f/1.4 Art remounted, using the
free service offered by Sigma. I dropped it in at CR Kennedy in Melbourne (coincidently both the Sigma and Pentax agents in Australia), and it was ready 3 or 4 days later.
The new mount seems to be the same size as the old, except bevelled on the edge. This is enough to prevent it from scratching the K1 body. It looks like a very professional job. Well done CRK! Given the ease of the process, there's no reason not to get the mount upgrade.
By the way, this lens performs flawlessly on the K1. I had consistently suffered 1-1.7 ev overexposure on the K3, but it's perfect on the K1.