The reason for the switch
The IMBD has elected to call his page "Amos Burke: Secret Agent" noting that it's original title was "Burke's Law". True fans know the title was "Burke's Law" and that "Amos Burke: Secret Agent" was an abomination it was turned into in it's third season. Many feel the show might have gone on for years, like "Murder She Wrote", "Columbo", "Diagnosis: Murder", Matlock", etc, all shows that people who worked on Burke's Law later were involved with. With a normal run, it might never have left syndication.
There's some discussion on this forum as to why the switch was made but nobody seems to know other than the fact that there was a "spy craze" at the time.
On U-Tube, one poster, calling himself "fromthesidelines", has this to say, (his post might be archived at some point so I am quoting it rather than linking it):
"These are the closing credits from the very first episode of the "revised" series (which producer Aaron Spelling insisted wouldn't work, but ABC wanted a "spy show", and they and Four Star insisted Spelling "convert" Amos Burke into a government agent)"
I don't know if the poster really has any inside information but it's the first time I've read any specifics on the subject so i thought I'd share it with everybody. Apparently we can blame the network and the production company, not Spelling and certainly not Gene Barry, (one poster here said he wanted more screen time and wanted them to get rid of his co-stars).