It's a shame that I can never be certain of anything anymore unless I test the disc myself!
I had assumed that the "Fleetwood Mac" DVD would have DTS audio on it based on both "Tusk" and "Mirage", but I missed the warning sign last year that was Rhino's reissue of "Core" by Stone Temple Pilots, which had a Dolby-only 5.1 DVD in its box set.
Oh well, at least I was able to cancel my box set order for "Fleetwood Mac" before it shipped. That's much easier than dealing with the hassle of sending it off after it's already arrived, which was the case for me with last year's Bruford box set.
As for the other upcoming 5.1 DVD releases ("Roxy Music", "Heavy Horses", and "Fish Out Of Water") if all of them have DTS audio, great. If not, I will send back whichever ones do not.