Here's what's installed on the Montana 5er line from information I found on different dealer websites:
Rear Hitch
Rear Hitch Type Receiver
Size 0.17 ft. (2 in.)
Size (cm)5.1
I checked the factory installed receiver hitch on my Montana and found the weight limitation sticker under the trailer on the cross member part of the frame the receiver is welded to. Here's what it looks like:

This image may be hard to read, so here's what it says:
Warning
Cargo carrying accessory receiver only.
DO NOT tow any trailer or another vehicle.
Maximum load capacity 300 lbs. (136 kg) including the weight of the cargo carrying container or equipment.
Use for towing or exceeding load limit will void the warranty. Failure to follow the instructions can cause the carrier to collapse or items to fall which could cause an accident resulting in death or serious injury.
My suggestion? Use the hitch with caution. Absolutely do not add more than 300 pounds and absolutely do not use it for towing anything.
Look under the trailer on the cross frame and you'll find the sticker.
FYI, we've had our 2019 Montana High Country 375FL for 4 weeks now. Very happy with it.