Yeah, not ancient, but only RCA inputs, and speaker wire outputs. It's a Sherwood. I guess it's a gen 1 surround receiver. It has front (A and B), center and rear speakers, but no sub out.
But why are those u things there. Do you think they are dummy plugs, or make a connection? If a connection, why just the center and not the outside ring og the RCA ports?
Edit: I see some of the above was answered as I was slowly smartphone typing.