Does 85 GMC 305 have O2 sensor ?

[C-10 simplex]

P.S. Right now, i think the blue plug thing is the mixture control solenoid IF the truck has CCC. If the truck is an 85 or 86 model AND DOES NOT have CCC, then it's a dual capacity accelerator pump. But apparently, a truck could be an 85 or 86 model AND have CCC AND dual capacity accelerator pump AND a mixture control solenoid AT THE SAME TIME. Confusing? It's the GM way.

i got the info on pg. 64 of Rochester carburetors by Doug Roe. i think he's a former gm engineer or something.