It is an early #11 cab but no CMP was made with aero windscreens so I guess it was a field modification. I think you will find that the windscreen frame has been removed.
__________________
Cheers
Cliff Hutchings
aka MrRoo S.I.R.
"and on the 8th day he made trucks so that man, made on the 7th day, had shelter when woman threw him out for the night"
MrRoo says "TRUCKS ROOLE"
