Just be aware that HP's pistols don't have a under-rail that's picatinny or weaver in fitment. It's their own proprietary width and cross pin mounts to work. I don't know of any pistol light that will work properly for these, unless it comes from HP.
I wanted to put a sight on my 40 S&W(JCP) and ordered a under-rail wrap around slide mount, but the system wouldn't fit the JCP's rail. HP's use a much wider system.