If they don't have any imprints on them they probably aren't suboxone or subutex. Like mentioned above, suboxone are orange with a N8 on them and are an orange or pinkish color. As of now there is not a generic version of Suboxone on the market yet. Generic subutex are white and do have some numbers imprinted on them. I don't think there are any prescription meds out there that do not have some sort of imprint on them.
Sounds like he may be trying to pull a fast one on you. He may be trying to make you think he is going to get clean taking suboxone when in fact he is just taking "fake" suboxone while he is still taking dilaudid. When I said a "fake" suboxone pill it is probably just some kind of harmless vitamin or supplement.
If he did get a hold of some pills that have no markings on them there is no way I would allow him to take them. There's no way to tell exactly what they are. Could be very dangerous.
Hey there is a pill identifier on here should be able to get you that info. 8mg suboxone have N8 on them and are pink ocatgon shaped. I never saw the 2mg ones. Did he get them from a dr.or buy them somewhere