Well, I had hoped someone would post a more knowledgeable, definitive answer...
I'm not certain, memory is fuzzy, but I believe with the II came a change in sensors. Something about a foil tab vs. a black tab? We've discussed before there's a BIG difference (pinout!) between ColoRam II and ColoRam IT.
I am sure there are several differences, but the only one that I know of for sure, is that the power supply for the Coloram II could control 24 scrollers, and the earlier version could only control 12. I think, but I am not sure that the early version could do 24 frames and the Coloram II could do 32. The rest is up to a more knowlegable person to answer.
The major change with Coloram 2 was the addition of remote fan control.
To run the two types together, you will have to set the power supply and
the Coloram 2's to CR1 or 12-channel mode (under setup on the supply, and toggleswitch 2 on the heads).
Note this disables the remote fan control. Alternately, an eprom change can
upgrade 1's into Coloram 2, minus the fan off function, which was a hard wire change to the PCB.