No, no "prior active military service" was needed. Just the various members of the militia would have access. Granted, they would be "well regulated," so training would likely be provided ... and access would be regulated, of course.
And, somehow, from this actual history of the Amendment, certain folks determined which should have the biggest military in the world, basically no well-regulated militia at all, and just about everyone should have guns, guns, and more guns, to protect us from baddies invading our homes and FROM the government taking guns from us (when it was actually to have us protect the government from usurpation and invasion). And then try to pretend like they were upholding the true meaning of the Amendment, and everyone else just wanted to disregard what was written and meant. You couldn't make this up if you wanted to. And you wouldn't want to.