what the heck is this?
 

I am wondering what the number that is stamped on my firewall directly below the cowl, it is on driver side of the truck right above the wiring harness and is stamped onto the ridge

the #
1 6 or G (i could not tell) 939

i was just curios as to what that number was

is that part of your vin number?otherwise maybe if it was a fleet truck it was tthe number posted in there for that? i know utility comp[anies did stuff like that here in the ny area