Thank you both for your replies! This actually is not for an EUC, it is for the no longer manufactured DualTron Man. MiniMotors OEM battery fried on me (it was li-polymer which apparently has a pretty high failure rate in these machines) and so I got a company to build me a li-ion battery to specs. They made sure to emphasize connecting the positive and negative terminals and to never reverse, which I knew... but there word of caution makes me hesitant to use anything but their supplied charger. I just fear that there is a small chance that the polarities could be reversed on the charge doctors and while not likely... that would be an expensive mistake.
I am not very well versed with the technical aspect of how to measure the polarity with a voltmeter nor how to interpret the readings once I do. This is for a 60v, 19.2ah battery pack.