That is what I have heard. But in the Free video,it looks like there are 3 mics, 2 with windscreens.
What is interesting is that at Woodstock, they recorded it, and just used 1 mic per vocal.
I guess there was no "Standard", or else something else was going on. I don't know for sure-but have wondered for years.
I'm not totally sure if that's a third mic.
There is the obvious silver one with no wind shield.
But the rest of it seems to be a single mic, that for some reason has a windshield over the transducer end, and also for some reason over the XLR entry end. The XLR (or whatever cable it would have been back then) seems to go straight into the bottom windshield, rather than that being the head of a third mic. Is most obvious in a good close up around 1:16 to 1:18. And it only looks to be two cables coming from the taped together rig, not three.
He seems to sing exclusivly into the silver one, and the black with the windshield captures his voice a little more off axis, so could be a recording mic, or maybe without a splitter system to duplicate the output, maybe the second mic is for the wedges? Or even if the desks of that time couldn't "send" a second copy of an output to what would have been a very basic FX unit, something like that?