I'm building up an old steel specialized frame to be my backup bike. It has a 7-speed shimano cassette, but no rear derailleur or shifters as the previous owner was trying to run it as a SS. I'm hoping to build it up as a 1x7, using a 7/8 speed shimano rear der. I have laying about. From what I understand and could look up, the 8-speed Ultegra barcons would work with this setup, both indexing and friction modes, so I ordered a set. Unfortunately the shop delivered a set of old Dura-Ace 8-speed barcons, and I'm hesitant to try to use them and find they aren't compatible and be unable to return them. I tried to make sense of Sheldon Brown's compatibility charts, and I think running the barcons as friction shifters I shouldn't have a problem, but I wanted to see if anyone out there might be able to stop me from doing something stupid in case I'm missing something important. Any thoughts?