Age of Carrier ACs?

M 38YRO30300
S 5190E12725

Is it Dec 1990?

M 38CKC036350
S 3802E02125

Is it 38th week of 2002?

For Carrier, Recently (last 20 years or so) the first four numbers in the serial number represent the week and year. So, your dates should be correct

Correct…