The best way would be to find someone with a CD player with the HDCD chip in it. That will tell you pretty conclusively whether HDCD was used or not.
However, even if a track has the HDCD markers, it may or may not have any actual HDCD code in it that effects the sound. The Pacific Micro A/D/A was one of the best ever made and many producers used them even if they did not use any HDCD features. So, many tracks show up as HDCD but there is no actuall HDCD code in the track other than some markers. Matt put some code in MC to not report a track as HDCD unless there was actually HDCD code, not just the markers. Hence, some tracks that people think are HDCD are not reported as such in MC, since there is no real HDCD code in them.
HDCD is proprietary. Pacific Micro licensed the chip makers who did HDCD in the CD players, so they are generally taken as giving good results. PM sold HDCD to Microsoft who implemented it in WMP, so that implementation is generally believe to be based on the actual specifications. Other implementations, such as in MC, foobar, dPpoweramp, EAC, hdcd.exe, etc. are based on software that was developed to decode HDCD, but was based on the authors knowledge, not the specification itself. So, it is hard to know how complete those implementations are.
The foobar implementation is based on HDCD.exe (a different program than MC uses) and it has a facility to report the actual HDCD Extensions that that were detected. That is one place to start to find out just what might be in your CD. There is a discussion here of the details:
https://hydrogenaud.io/index.php/topic,79427.0.htmlBottom line - CD players with HDCD detection and WMP should be accurate at detecting HDCD. Other implementations are very good, but since they are not based on the actual specifications, they may not be entirely accurate. And, even if any of these detect HDCD, there may not be any significant HDCD code in the track. The MC implementation complicates the situation in that it reports tracks with HDCD markers, but no actually sonic changes, as not being HDCD.
Good luck.