Resistance measurements vary. If you put your leads together it should read zero but most digital meters don’t have a zero function.
With this said I would be happy with 1.3 ohms knowing the value may be much higher and still be good. What you want to make sure of when the thermostat is turned above the current temp set point of off the contacts open or read very high values.
Remember not to take resistance measurements on a live circuit most digital meters run on 3v or 9v for there ohm meters and getting hit with 120v can fry the meter.
If a live circuit I look for a voltage not resistance. with the contacts open possibly 120 or whatever the control voltage is and close to zero when the contacts closed.
I just looked at the link those are thermal snap switches, they will be all or nothing but when controlling line voltages 10-15 ohms will be fine as they age maybe close to 50ohms as the contacts get pitted and eroded.