so I just got a set of duraace bar cons and they say they are only to be used with a dura ace rear, is this hogwash?

Sort of. DuraAce BEFORE 9 speed only worked with DuraAce. With the advent of 9 speeds and more they changed all of the rear derailleurs to work with the same ratio as DuraAce.

So as long as you're not trying to shift 8-speed or earlier rear derailleurs you're OK.

I don't think theres any difference between Shimano 9sp barcons, a barcon is a barcon I think. Mine work fine with an 8sp Ultegra rear derailleur on my cross bike, and I have another 9sp set on my tandem that work fine with a cheap old 7sp RSX MTB derailleur. I like STI for road racing, but barcons rock for cross and tandems.

I am using an Ultegra barcon with a campy 8-speed cassette. I don't think anything matters in friction mode.