If the top & bottom are a really sloppy fit, rattling as you wield the rifle, then maybe the wedge will quiet it down. And if that quiet solid feel makes you shoot better then it was a good idea. I don't think it'll do any harm, and I don't think it'll make the gun more accurate - everything to do with aiming is on the upper part.
If the top & bottom are a pretty good fit, not much movement, then it's probably not worth getting a wedge or tensioning pin.
Regards.