Tom, look at the long line of stamped numbers on Michael's pictures of the cooling air cowl. The numbers are in the yellow oval in this copy of the picture:
[Linked Image]

As you can see, they are just stamped into the rusty steel, so you need to look hard to read them. We need the whole of that long string. The first group is Model, the second group is Type, and the third group is Code. All of it is needed for our current purposes.