2.0 vs. 2.0 Surround

[italy12]

Since some Blu rays are encoded in something Universal uses a lot called DTS-HD MA 2.0 mono (same sound from R and L speakers), and some are just DTS-HD MA 2.0, like titles from Scream Factory.

Then Criterion uses DTS-HD MA 2.0, but they say to use the PLII decoder to get the surround activity to replicate the original audio or play as it was originally intended, etc.

Older DVDs used to say, specifically, Dolby Digital 2.0 Surround if it was flagged as a surround mix. For example, I popped in the Poltergeist II/III flipper DVD the other night and both films show up as Dolby 2.0 SURR on my Onkyo receiver.

DTS-HD MA 2.0 mixes always show up as that, never Surround.

So, my question: how can one tell if the mix is intended as 2.0 mono, 2.0 stereo, or 2.0 surround?

Thanks!!