Apparently, there are 2 sets of color codes for the Motorsport Tri-Colore from what I've found out. Here they are :
For painting -
Blue -Violet Glasurit/BMW 4000
Light-Blue Glasurit/BMW 5002
Red Glasurit/BMW 353
For printing -
Blue: Pantone Process Blue
Purple: Pantone 268
Red: Pantone Warm Red
Neway, hope that these helps and do run them by your painter just to be sure!
Cheers,
VaN.