Hi bike-tech gurus.

I found a 'set' of barcons at my local bike co-op, but they are both for the left side. One is an sl-bs77 and the other is an sl-bs64.

If I'm not fussy about indexing, is there any reason that I can't use one of them on the rear of a 9 speed set-up? I'm thinking that given the physical symmetry of the shifters in a given set, the amount of cable that a either the ultegra or dura-ace barcon pulls is likely the same on the right and the left... am I missing anything?

Thanks in advance.
Neil