I have a 1955 olds with a data tag on the drivers side door area where it normally would be. How do I decipher the info to make sure it matches the car. The first tow digits are 55 so I assume this is correct for a 55. The last 5 digits are the unit serial number. There are two digits in between, which are a 7 and a L. Anyone know the meaning of these two? Thanks, Steve G.