I watched this, quite content to follow the joke, although the 'spoof' seemed to lack a bit of (well, a lot of ...) the Spinal Tap magic. This evening, I thought to check, and am amazed to find that it's not at all a joke; that they were, apparently, briefly famous (I've never heard of 'em, but what would I know..?), and that there really was a reunion gig..! The laugh's on me, I suppose.
As a 'real' film, I don't think it stacks up at all. Maybe for fans of 'em..? I'd have been better served by not checking and continuing to take it as a spoof..!