Fatman: As always thank you for your comments and insights. Those of us now in our 70's do sometimes forget that the era just before the war was one of uncertainty and "make do" for many manufacturers. As you suggested, I did check the Binns Road site and saw my Pullman with a GREEN roof! Now I have another variation to hunt!! 
. The Hornby No.1 Pullman roof does indeed look like a perfect match for my "odd man out" Pullman and your speculation on how it ended up on a French Pullman makes perfect sense. I can attest that it is almost certainly a factory installation as there are no tool marks to indicate that the roof has ever been off or changed. I also appreciated your comment that the small drop link and the automatic couplers were both in use at the same time. This supports the dating that I mentioned.
I also don't have Mr. Lammings book, for about the same reason you don't have it, but I will give you a reference on British Hornby that you might not have and it is more reasonable in cost. It is..."The Hornby Companion Series , Vol 5, the Hornby Gauge O System", Chris and Julie Graebe, New Cavendish Books, 23 Craven Hill, London W2 3EN, Distribution ABP, North Way, Andover, Hampshire, 1985. Now 35 years old but its a reasonably good book with excellent high quality pictures but like so many of these books the concentration is on freight wagons and the more expensive passenger sets. Their coverage of French Hornby (1 fairly brief chapter) and export trains (1 additional brief chapter for the rest of the world including the US) is not very detailed. One item in the book that I do find useful is a detailed appendix giving the years of manufacture of every production item listed individually both pre and post war including sets.
Again, I want to thank you very much for responding and providing your insights.
jhz563 : Your posting made my morning! I loved the idea of using the Kroil oil can as a waste bin. The lithography on the can is first rate, colorful and the "big drop" image is just a hoot!! Just let it "air out" for sufficient time OUTSIDE to remove the volatile components which can be a fire hazard and use a strong detergent to remove any oil film. Sorry, I am a safety guy and worry about such things. Great find and great idea for re-use.
Sincerely
Don McErlean
