Michael,
I have always understood them to be Topping. The ones I have were sold to me as Topping. I have two original Topping marked boxes for the miliotary versions.
Here are three airline versions:
And the same mould was used for the C-135 and KC-135
Notice that the same mould was modified to simulate fan engines on later models. Sorry about the poor images--they are old files on my computer. If you like I can shoot better ones later. Since these were shot some years ago I acquired a 707 in house colors from this line. They seem to bring good money on ebay even when in damaged condition.
Cheers,
Ladd