Glen was a touring bassist, guitarist, (and occasional banjoist) between December 26 1964 and May 15 1965, with both Brian and Bruce filling in for some dates during his tenure. None of the Beach Boys tracks recorded during that time features Glen on bass. He did however play 12-string acoustic rhythm guitar on "Please Let Me Wonder," "Help Me Ronda," and possibly 'Help Me
Rhonda."
Here's a timeline that I prepared some time ago:
https://www.mediafire.com/?z03j76iw9x0bqxxReferences
Aniversario, E. (2012). The Beach Boys setlist archive. Retrieved from
http://members.tripod.com/~fun_fun_fun/set60s.htmlDoe, A. G. (2013). Bellagio 10452: Take all the time you need… a Beach Boys reference site. Retrieved from
http://www.esquarterly.com/bellagio/gigs65.htmlRusten, I., & Stebbins, J. (2013). The Beach Boys in concert: The ultimate history of America’s band on tour and onstage. Milwaukee: Backbeat Books.