Long Wheel Base Truck

[delta31]

After working on the truck we bought months ago. We just recently realized that our vehicle had a wheel base of 126 inches.
It doesn't have a rear bed and we discovered the long wheel base while measuring for a bed. I'm assuming that this is an M56.
The data plate reads M37 and it had a 100 amp charging system.

Are these long wheel base trucks considered rare?

Any ideas of why the data plate is marked M37 instead of M56?

Thanks

[RMS]

not up on m56s but I almost put a m37 cab on a ambulance chassis and was going to make a long box out of 2 m37 boxes. I have a few box sides I would sell if your in the pnw

[Cal_Gary]

It could be an M201 Maintenance truck as well with the longer wheel base. They are fairly rare as I recall. No idea why it would have an M37 data plate unless it (or the cab) had been changed.
Gary

[RCrombie]

I have the same data plate issue. M42 data plates on my m37Cdn. I guess glovebox doors get swapped around?