The last of my Vin is 393803 That is 4,720 After your May build date The Car does have a Cowl tag that says 442 And a number Lacquer Paint
I will try the Dealership and see if they can trace my Vin back to a build date 'Wish me Luck'
Based on that info, there was an average of about 7700-8000 sequenced vehicles per month, SO....just extrapolating (aka WILD *ss GUESS), you may have a build date of 05C or 05D or at worst 06A. So you already know it MUST be at earliest a 05/86 build month. I seriously doubt a July 86 date based on 4700 vehicles. They used to shut down around that time frame anyway for 4th of July at some of the plants. Don't recall what the end week of 86 production was in 1986.
Look at your cowl tag. A picture would be better, but if you can tell what MIGHT be some numbers at the top left corner, there may be clues. Is there a number/letter combo up there? The bottom row usually has big options like car color and all that, but the top left might have the build month/week. For example, 05A is first week of May. 05B, second week of May...and so on. Does it have something like that? If so, that'll nail it down.
