Same thing with Barney Miller
Stuart Margolin (spelling?) I believe played Angel in the Rockford. He played the plastic surgeon in the earlier season episode about the nose job and who found The Barracuda at the 4077th.
I've been on a Barney Miller kick the past few months and have found the same thing. And I'm guessing I'd probably see these actors on other 70s-80s shows as well. The actor that played the Greek officer in Private Charles Lamb played a couple different characters in Barney Miller. Seems like Todd Susman showed up in Barney as well.