Yes, in theory the introduction of buprenorphine can precipitate withdrawal, thus reversing an OD. The odds of this working improve those closer administration is to the earlier administration of the agonist, the higher the dose of buprenorphine, the level of existing dependence to the agonist in the victim and so on.
Obviously the first thing to do is to call for help. The success rates of paramedics almost surely will be better than your guesses. With that said, if for some reason you are unable to call for help and you fear that someone, yourself or another, could end up dead, then a reversal can be attempted at home with these drugs. Obviously straight naloxone is best, but if only Suboxone or buprenorphine is available, that can work too. IV is not required for this to work (and the time you spend preparing the IV will negative the quicker effects of that route of administration anyway). Just put it under the person's tongue, and in this case more is going to be better. There's no risk of OD from bupe or naloxone in such circumstances.
Obviously it's not a guarantee that it will work, but it's better than not trying at all (again, assuming that calling for help is not an option).
