I would assume so, but Madcow might need to chime in as it's been a while since I have seen the stock Shimano connectors. I would assume that the connectors on the road levers are the same as on the TT levers, but I don't remember for sure. I don't use the Shimano levers with my Di2 setup and my hair started going grey a couple years back, so my memory isn't what it used to be.
Or if you can find a good pic online somewhere to show the TT front wiring harness and the road front harness perhaps that will tell you?
I have to say it though - why don't you just make your own buttons? There is so much $$$ to be saved that way. If you can splice the wires together yourself, of course.
Have you ever wondered if there was more to life, other than being really, really, ridiculously good looking?