[70cst]

The following was taken from the American-Light Duty trucks 3d Edition. I would assume this would include the Blazer, Pick Up, and the Burbs. As has been said before GM was not real good in keeping specific facts back in the 60’s or early 70‘s. I hope this helps.
[COLOR="Green"]Heavy Duty seat(3%), CST(6%), Chrome Bumper(18%), Custom & Appearance Option(28%), Full Foam Seat(23%), Painted Rear Bumper(16%), Rear Step Bumper(16%), Heavy Duty Cooling(1%), Chrome Rear Bumper(2%), Courtesy Lights(99%), Push Button radio(41%), Tachometer(1%), Speed Warning(Not Available), Side Marker Lights(NA), Cargo Lamps(NA)< Camper Wiring(2%)<,Roof Marker Lights(2%), White Wall Tires(13%), Side Mounted Wheel Carrier(11%), Chrome Hubcaps(11%), Wheel Trim Cover(19%), Hydraulic Steering(21%), 350 Medium Duty V8(8%), 350 Light Duty V9(32%), 292 six-cylinder(14%), SS-396 four Barrel(4%), Heavy Duty Clutch(28%), Overdrive(1%), Four-Speed Manuel(17%), Heavy Duty Four-Speed Manuel(1%), Power-Glide(5%), 300 Deluxe three-speed automatic(10%), Hydraulic Brake Booster(14%), Positraction(7%), Power-R-Lock Rear(1%), No Spin Rear Axel(6%), NA-means installation rate not known.I did not see AC info but in 1970 16% of the trucks had this option. Nothing about the bucket seat option. There are other options most likely not listed but this should give you an idea to some of the options avaliable. As you can see the creature feature options were not in high demand at this time. But it is with the 67-72 Chevy/GMC trucks that car like options were avaliable and trucks were being considered as an alternative form of transportaion along the the car. Merry Christmas!!