Soundcraft Delta AVE Module Swap

I have the 16 channel Delta Ave Console with all mono channels. They are all RS5060 modules, and I wanted to swap a couple out for the stereo RS 5061 Modules, but am not sure if my frame supports them. I have already opened it up and first thing I noticed is that there are two 3 prong connectors under the fader on the RS 5061, but I only have the one 3 prong cable, is that the second channels connector? How can I tell if I have the proper frame? Thanks in advance for the help, I really need a few more channels and can't imagine having any bigger console than I do already.

Soundcraft Delta AVE Module Swap