Did you ever hear of Indorock? The Tielman Brothers?

[highplainsdem]

4. Barry Hay did at least one broadcast tribute for Andy Tielman, according to

more sources I found online since I posted that last reply. He also wrote about the Tielman Brothers in his autobiography. I'll try to get some of that translated from the Dutch tomorrow. Too tired to type it into Google Translate tonight.

And I found a discussion on a Les Paul forum about that guitar George bought - https://lespaulforum.com/index.php?threads/three-pickup-custom-played-on-radar-love.175719 - and according to Dutch guitarist Peter van Dorst, a friend of George's who was posting there, George had bought the guitar from Reggie Tielman, Andy's brother. In which case it might be that black guitar you see in the first video in the OP. See this 1975 video from Winterland (guitar solo starting at 3:15):

This page of photos Joe Bonamassa posted on Facebook - https://facebook.com/JoeBonamassa/posts/10158620602649659 - shows the spare Les Paul that George had sold in 1976 and Joe had just bought, as well as a photo of George holding the same Les Paul as in the Winterland video. The three pickups look different because George had uncovered the black bobbins on the guitar he was using, the one bought from Reggie Tielman, and apparently left them covered on the spare guitar he sold in 1976 and Joe bought a couple of years ago.

Same guitar in this 1971 video, from a Dutch TV appearance. You get an especially good view of the guitar starting at 1:40: