What was the deal with Glen’s hair/wigs?

When he was “Gary” he looked like he had a receding hairline with thick hair all around one length but combed over. Assumed that was a wig. But was the high forehead his real hairline or part of the wig?

As “Ron” his hair looked amazing (more line the real Glen Powell) but also had a high hairline but somehow it looked great. Assume that was his real hair vs Gary it was a wig?

Then at end his hair was like “in between” both styles representing hos character was. Ie more of an amalgam of Garyband Ron. But was it all his hair or sometimes wigs?

If that was his real hair the whole time the hair people were amazing! And goes to show what a little styling can do!