Anyone else notice that Carl wears 4 different straw hats throughout the series?
There's the one from the scenes shot in Chicago, which has an oval shaped crown, two rows of double tier vents around the body of the crown (with a number of the vent holes missing or clogged), and the brim turned down in the front:
There's the "hero" hat A, used for the first 15 episodes (and two TV movies), which has a crown pointed in the front, larger vent holes, and the lower of the two vent rows (and part of the upper row on the right side) obscured by the ribbon, and with the brim turned up all the way around:
Showing two rows of vents along the crown in the interior view of hero A, with light blocked from coming through the lower row by the ribbon.
There's hero hat B, which first shows up in episode 16, Demon in Lace, and is used until the end of the series, with two rows of double-tiered vents, up turned brim all round, and a crown pointed in the front:
And finally, there's a "stunt" hat that was used in the sewer scene and wraparound scenes for the Spanish Moss Murders, with two rows of vents and an upturned brim all round. At first I thought this might be hero B, but then I noticed that the vent holes were a bit bigger and the top of the crown isn't as pointed and is crushed down a bit in front: