If it was put on your car at the factory and has a

[DW31S]

That stuff happened at other plants, too. I know a guy here in Maryland (actually twin brothers) who assembled Chevelles at the (now defunct) GM plant in Baltimore. He tells me how he ordered a Monaco Orange/White/White SS396 Convertible for himself and his brother. Well, mysteriously that car somehow left the line with a 427 under the hood. It also had a few more creature comforts than the build sheet reflects. Another good one is this.....while my father managed "City Olds" in part of 1965 (he also managed "Anderson Olds" in part of 1965), a certain White/Black '65 Cutlass 2dr (NOT a 442) hardtop arrived off the car carrier with a 425 engine installed. One of the line mechanics bought it and surprised many a street racer around town with it. I try telling some newcomers in our hobby about stories like these and I am greeted with a raised eyebrow and a look like they think I've lost my mind. Only old graybeards like myself understand that while not common, this kind of stuff really did happen. The locomotive gauge discussed above is way cool and if I owned that car, would stay there for life.