Although this board is in deep coma I give it a try anyway.
Marcel Lehoux raced various Bugattis, among them 2 T51, #51128 and #51144. Raffaelli writes that the first one - #51128 - went to Louis Trintignant on 9 Feb 1933, contrary to this Conway reports delivery date of the new one - #51144 - as October 1933. As Lehoux raced extensively during the 1933 season one of these dates must be wrong. I'm tending to the delivery date of #51144, but would like to have also other opinions or even proven data.