TH 350 overdrive and Lockup converter?

[383drvr]

Hey guys,
Did they install overdrive TH350 transmissions in the 80's, (1983)? Mine had a cruise control harness going to the trans, and I took it, and the rest of the cruise control system out. (I think I regret it now). So does this mean I have a lockup converter and an overdrive transmission?
I'm getting ready to replace the trans, that would suck if I have to replace the expensive lockup converter to keep my (existent?) overdrive.

I do think I feel a difference in the rpms I'm driving at at highway speeds since I removed the cruise control. Do I need the cruise control harness and computer to make it shift into overdrive, or is that operation concealed in the transmission itself?

Thanks in advance