Except they were not Northstar. I got them out if their racls today and they were all white, with no brand name. They only thing it said was Pb (the periodic symbol for lead) and there was a small sticker with a serial number. i think they may have been made by a government contractor, since they were in a government vehicle.
Get the voltage checked. They are probably long lasting batteries if you keep them charged. If nothing else take some pictures and see if you can trade or sell them. Did you have any luck finding a manufacturer’s name tag on the vehicle? It would be great if you could get build information from them, they might even have a wiring diagram. Maybe it would be good to PM Jimindenver see if he can help you as well.