Mono vinyl, how do you know if really single channel mono or if stereo recorded to mono


I'm exploring the possibility of getting a mono cartridge. 

Please, I am not trying to start a debate about whether or not that is a good idea. I simply have a question about monophonic records.

How can you tell which records are truly mono and which are actually stereo with 2 identical channels to simulate mono?

I know that for all mono records before stereo there was only one channel cut laterally into the record .  When stereo came out some so called mono recordings were actually 2 channels just like a stereo record with both horizontal and vertical information but  L and R were the same so ended up as mono. I also know that a "true mono" cartridge only has output from the horizontal motion and that the stylus size is different than a stereo stylus, which means according to many aficionados of mono recordings,  in an ideal world you would want a cartridge optimized for mono to play true mono records

again, I do not want to debate the pros and cons of this, just want the facts about the records. If you want to debate something else please start another thread

thanks


herman
Tablejockey, No, I am referring to June Christy, not Julie London. I well know the difference between them, and I own albums by both artists. June Christy started her career shortly after WW2, before Julie London hit the scene. She was briefly married to the bandleader, Stan Kenton. She started her career singing with the Kenton band. She was later superseded in that band by Chris Connors. June Christy’s album “Something Cool” is a jazz vocal classic and one of my favorites. Which is why I own both stereo and mono versions.
Once I understood and heard what mono is all about, stereo just adds to the "its not real, it's a recording" reality.

Now and then, the mix in a stereo LP is believable.  I just don't get the thinking-putting vocals on one side? Vocals should be mixed to both channels so the speakers can do their work "imaging". I do think mono thru 2 speakers is more convincing.

If you want to be real obsessive- listen to how a rock drummer blows through his kit. It should pan right to left(that's how it is live" if you're facing the band) Only if the drummers  playing orientation is the opposite should it pan the other way(not common). Many recordings are backward in this regard. Listen to the hihat. It should be on the right speaker. I don't know if this is a "reverse phase" phonomenon situation or what? Certainly isn't my particular amp. I sometimes reverse leads on the table for this.

I've noticed this years ago, and anytime my drummer friend is over for a listen he immediately notices it. 
@herman  Good choice to go to the top in buying a Miyajima Zero.  I have a Miyajima Premium and, even though it is maybe not a perfect match for tonearm, it sounds great.  Much better focus and tonality than using a stereo cartridge and a mono button.
I just bought a Phasemation mono which is even better on my Technics 1200G arm.
Nice.  I predict you will love the Zero and you will enjoy your mono collection immensely.
Those funny fake stereo mix is often related to records from the 60's. It's weird when vocal is only in one channel and drums in another channel ans so on. 

Records from 70's normally recorded and mixed in stereo properly. When we say STEREO it's a proper stereo mix, not a fake early stereo from mono master and stuff like that.