Absolutely saw him on the 12 string. It was quite a show, done about a year before the Friday Night album came out. They each took turns on 6 string and 12 string axes with brief solos on each. No question that McLaughlin was the master of the 12, though. Simply electric! The album actually didn't do the show justice because they played for about 2-1/2 hours and most of the material never made it onto the LP. I didn't even buy it until a year or two ago when I found it on blow-out at Borders before they went under.
To my everlasting disappointment, I accidentally recorded over the 2 TDK SA 90 tapes used to catch the show. I stupidly forgot to relabel them after the show was over. When I went to edit and dub a few years later, I discovered I'd put a John Valby show over most of the material. Only about 5 minutes or so survived. Doh!
Got to see UK with Bill Bruford and Allan Holdsworth open for DiMeola's Casino tour back in '78 or '79 at the Santa Monica Civic. Al played 12 string when he covered Mediterranean Sundance. Then we got the real treat - Chick, Stanley and Lenny came out to do a 45 minute improv as the encore. Those were the days!