The ones that I saw were colored, as I recall. I'm surprised the manufacturers didn't come up with something like it sooner. The guy at Fry's said if you buy a Sony you'd have to have Sony speakers etc.
You can see that the Sony connectors are a twin plug, two wires, one for (+) and one for (-) phase, it's been that way forever. Your helper at Fry's is wrong. You could either use an adaptor or hardwire splice into any brand, type, model of speaker that is compatible, i.e of the same impedance. Back in the day, Pioneer used a proprietary connector as did some Euro stuff.
I'm still not clear if this audio gear is 12 V or 120 V. I'm guessing 12 V as most are that way. I'm one of a few that use 120 V audio gear.