CM AQM was added as an optional feature in DOCSIS 3.0. I don't know of any 3.0 modems where this was actually implemented though.
This feature requires no support from the CMTS/CCAP chassis, so as long as the modem supports it, it will work, regardless of the supported DOCSIS version of the CMTS.

I have verified AQM working with the Arris CM8200A, the Technicolor TC4400, the Hitron CODA-46 and the Hitron CODA-4582. AQM is on by default on these modems, so unless the ISP is intentionally turning it off, it'll be there.