There is a very simple way to identify the 350C, which is the lockup version. There will be an electrical connector above, and just to the rear of the manual shift linkage on the driver's side of the transmission, and the input shaft where the torque converter slips on will be hollow, with an "O" ring in a groove about 1/4" back from the front end of the shaft. Standard 350's do not have the O ring, and the input shaft is solid. The pan shape you're describing fits both 350's and the "C" model lockup type. If it looks like a 350, but does not have a vacuum modulator, just a TV cable, you've got a Turbo 250.
Jerry
