You'll want to have a hand held light anyway for any search task, since otherwise, you're pointing a loaded gun at everything you look at.
My experience and research both indicate the primary culprit in problems with Glocks and lights was the Glock in .40, usually in older models and usually with a light which was screwed down to affix, and sometimes screwed too tight. Glock assures me that the problem has been solved in current production.
My own Glock 31 wears a light more often than not (a Surefire, which does not screw-tighten to mount) and I've never had a problem with hundreds of rounds with the light affixed.
You'll want to run a few hundred rounds through any new handgun before you trust it for HD/SD anyway. Include the light in the test. If there's going to be a problem, it should show up early.