Ross, you honor me by thinking I can remember intimate details about church broadcasts dating back to 1961!
Back then we used a line amp with two mic inputs and one line output; an ugly black box that, once set up, had only one feature that required attention two times per Sunday - an on/off switch.
Tapes? No! This was live stuff!
I don't recall anything that stands out as far as the Presbyterians were concerned except that they had a minister who was a ventriloquist!
There was another church, however, that was unforgettable - the minister insisted that the more microphones used, the better the broadcast. One Sunday he was pleased to see FOUR mics; little did he know that only ONE mic was live, the other three were duds. That preacher assumed that it was the best church service ever!
Sorry I can't be more helpful. If any tapes exist, they weren't produced by WJMA. In retrospect it would be nice to have a bigger and better audio history.