Most Rats up until mid 2000's used CTS pots.  To determine the date of your Rat find the 7 digit number on the back of the pots.  The 1st three digits are the manufacturers code.

137 = CTS (Chicago Telephone Supply)

The 4th and 5th numbers are the year made  (example: 1378509)

1985 would be the date for this pot.


(below) This is a pot from a very early "Fringe logo"  Big BoxRat.  Date code is 1979