It occurred to me that if painted apple green the front edge of the cab is typically black, so would join nicely with the longer bulge on 2509 as built. However I then thought to have a look at a P2, and I found this image of 2001 with the bulge in line with the v!
Photo copyright from Douglas Miller from gettyimages
Also apologies for mid-conversation username change, I made this account years ago and forgotten until this discussion that I'd picked a slightly strange one!
Adam