How to buy a used Helblad 500cm?

That was a mithical camera. I never had one, but you can find some not difficultly. You must check all your list. If the lens is original Helblad too and lens fits correctly to the body. Won't be easy to detect light leakings at the store. ure what model exactly is and the year it was made. Check the film magazine too. The shutter speed should work properly, check in the seconds scale