I think he also displayed a Model 12 Airweight on the show.

Someone here posted awhile back that the LAPD Academy has some of his guns on display.

I think a Model 15 is more likely as the LAPD did not allow .357's. (Model 19.) Model 15's appeared on the other LAPD show, Adam -12. Martin Milner is in ill health now, supposedly, and someone posted that he's trying to sell the gun that he carried on the show. Those M-15's had custom grips by John Hurst.

Raymond Burr (Perry Mason) was also presented with a Model 29.