I got my box of headlight control modules mixed up. My 1990-2002s are combined with the pre-1990 modules. On the circuit board in the bottom left corner is a 'two digit "dash" two digit code', such as 15-87 or 51-93. Is the second number always the year car this module came off? This second number always seems to be consistent with a 3rd gen or 4th gen year on the dozen or so I have. Thanks - This saves me from plugging every module into my own car to figure this out.