The wordpress drawing and the 1971 pic in the HuffPost article confirmed my recollection. I also found pics of a diecast vehicle in the proper scheme but the lettering looked large. You can see the lettering size on the P-700 through the windows of the box van in the 1971 pic, and the lettering size in the wordpress drawing is discernible even with the sharp angle.
Thanks, these are exactly what I needed as confirmation. I picked up resin two package vans from ChuckThePrinter on eBay. They are extremely well done, and are pre-painted which I didn't expect. They have no markings though, so I have to add them.