Sure - I still have 1/2 life on my stock pads.
I think for street driving it wouldn't be an issue - they should mate up over some time. I can't see them actually causing any damage besides cleaning the rotors a few atoms while mating up.I can see for the cost trying to salvage the DTC70's but I see a risk that could become troublesome on the new car. You have old pads seated into a set if disc's and calipers now you are not only moving them to brand new disc's but also calipers that while "identical" are ever so slightly suspended differently, a milli here a milli there and the pad is in a whole new world to try to adjust to.
I wil not mate old pads to new disc's even on the same car, just IMHO.