The hats worn by Gerald McRaney in the Simon & SImon series were in fact wide brimmed Panama hats. I discovered the maker of these elusive hats (won't find any online. have to be custom made for about $600-$1200 dollars) .
The tight weave of the straw actually looks like "fur" on camera.. extreme close ups of the hat on the show will reveal the weave pattern of the hats.. ( I count approximately 10-12 slightly different styles, brim size, crown pinch, etc. throughout the shows 8 year run.) I personally have always loved the hat, and have owned one like it since 1983.. Naturally I also have had about 10 of them by now.. LOL