Need help identifying this thermostat assembly

[WNC123]

I could use some help in identifying this Behr thermostat assembly. The part number 001 203 11 75,when I search, just comes up as a thermostat assembly, so not much help there.

The housing is metal, the thermostat is not removable, so the whole housing would need to be changed if the thermostat went bad.

Does anyone recognize it? What year(s)/model(s)/engine(s) was it used on?
Thanks for any help.

[Paulwho]

w189 Mercedes 300d engine 189 with air circa 57 thru 62