I'll go look into it when I get home since I have nothing else to do aside from play Order of Ecclesia. I will say that Japanese is actually a fairly simple language, though, and a lot of Japanese Mega Drive games are partially or entirely in English anyway, like Vampire Killer, Alien Soldier, Jurassic Park, Gley Lancer, all of the Thunder Force games, Silpheed, and Eliminate Down.
Interesting that they would leave Jurassic Park completely untouched from the US version but still region lock it; it refuses to run when I have my Super 32X attached but works if I remove it. The text on the (original) US version's copyright screen mentions the Genesis, and I'm not sure if it got changed to Mega Drive for Japan/EU releases. I'll go dig out my Japanese cart and check when I get home.
The Contra Anniversary Collection has an option to play the PAL games at either frame rate, so you can have both of the two Probotector games at 50hz or 60hz. That's using software emulation, of course, but I think it probably should be no problem to use the 60hz code on real hardware or the Mega Sg. I tried it with Castlevania The New Generation maybe 6 months ago and the copyright screen actually said Bloodlines instead of New Generation. Pretty sure the actual title screen was still New Generation, but I don't remember. I think there are a few minor audio differences between New Generation and Vampire Killer/Bloodlines because of the frame rate difference (mainly the sound of the whip), and I don't remember what happened with those, either. The music is PAL-optimized. Interesting that the Castlevania Anniversary Collection does not have the option to run New Generation at all, and you have to play at everything at 60hz..
Edit: Looks like Probotector does not work with the code. New Generation does, though. It has some crazy stuff going on with the CRAM dots, but it does work perfectly. Interesting thing is that on my Nomad, Probotector runs at 60hz using the MegaSD's region fix thingy. Jurassic Park Japanese version still says Genesis on the copyright screen, oddly enough.