I found this in the FAQ section at the top of CUCV page , page 2 or 3 I believe
RE: Re: M1009 Key same as M1031?
Hey, I want in on this horse-beating rank-building stuff, too! Yeah, we all know that the blank is B and the blind code is 73Y2. I hear rumors that those details are in a FAQ somewhere... most likely in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying "Beware of The Leopard". But how about the cutting code: That's 313531! And the blank: Jet calls it a B49. Ilco uses yet another number; they call it S1098B! I could list the cut depths and spaces, but wouldn't it be better if I did that in a different post?
To use the key, insert it in the lock and then turn it either clockwise or counterclockwise, as required. That would be deasil or widdershins, respectively, in very old vehicles.
I can't let a chance to post a picture go by!