The trigger voltage for that flash has been measured for 209V as noted on this website:
Photo Strobe Trigger Voltages
That makes it not safe for the Pentax DSLRs.
This counts for the hotshoe and the xsync socket as well.
You can use one of these safe sync devices which isolate the flash trigger voltage from the camera. Not sure exactly how they do it, it might be via a transformer or coupler. I've used a Wein device before. In the end, I prefer my Cactus V wireless transceivers because I can make my old flashes work remotely.