Revealing mistake: When Squad 51 leaves Rampart, in the first interior shot facing Roy as John says, "Yeah, I'll tell ya, when it hits ya. Boy when I met Valerie it hit me," through the back window we see movement at the back of the squad. Then in the shot facing Roy as John says, "So that's that... That's exactly how it is," through the back window we see a crew member's face (sideways), he has a mustache (John does not have a mustache), right behind John's head, as he's riding atop the back of the moving squad. (00:31:00)
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.