In his video, Secrets Of A Master Gunfighter, He trained with, and preferred a Glock 20 in 10mm. with an after-market barrel.
From Tales Of The Stakeout Squad:
"Toward the end of his life, Jim had become a Glock man. He used a Glock 20 with custom , extended 10mm barrel as a deer hunting pistol. His preferred carry guns were the Glock 30 .45 ACP compact and the Glock 27 subcompact in .40.....there were days when he carried the old hammer-shrouded Colt .38 too."
Yes that's right. I looked up the articles. He liked the G19. Said it was a good sized frame and fired an adequate load if the shooter made sure they used a good load, but he did not carry the G19.