DT 75 - Thermostat

[rconde]

After to disassembled the thermostat cover of my DT75, year 90 model, I realized that no thermostat was installed. However, I checked the parts for this model and I realized that there are two thermostats available. One for 42c and other for 62c.
My question is:
This model works with or without thermostat?
In case of working with thermostat which model it is, 42c or 62c.

Thanks

[mitch]

where are you in a cold water climate or tropical climate i would use the 62 in cold and 42 in warm