Yea idk where or how they come up with the build #'s. My sources show in 2006 Roush customized like 1835 cars, 510 sports, 640 stage 1's, 456 stage 2's, and 229 stage 3's. And yea in my model and color type 80 is what I show as well. 2006 Stage 1 Mustang (640 Total) D3 – Torch Red 80 – Coupe, Manual Trans, Grey Interior, GT 14 – Convertible, Manual Trans, Grey Interior, GT 8 – Coupe, Auto Trans, Grey Interior, GT 7 – Convertible, Auto Trans, Grey Interior, GT 1 – Coupe, Manual Trans, Red Interior, GT I checked my vin # awhile ago through Roush and it show's the build # of 1876 is correct. And I kinda like the centennial #! Model: Mustang Model Year: 2006 Body Type: Coupe Bed Type: N/A Engine Type: GT Transmission: Man Stage: 1 Color: Red Paint Code: D3 Stripe Color: None Interior Color: Grey Build Site: B50 Dealer: Harold Zeigler Ford Lowell MI Prod Start Date: 27-Apr-06 Completion Date: 3-May-06 Vehicle Serial No: N/R Build No: 1876 Roush Leather: No