I have to admit, I had intended this as a bit of a Socratic question, rather than a yes/no. But wow, I did not expect this thread to blow up so much!
Regarding the seller, yes, he was a legit engineer at a radar company. That said, it's not uncommon (especially in very large companies) for people to hyper specialize and have a very narrow scope of anything outside of their area. He was using it to measure attenuators he was selling, and perhaps that's all he did for the last 20 years in corporate as well. In which case, you're probably looking at the same screen, all day, every day.
Of course, he had something to sell and like a used car salesman who's only got one to sell, his was going to be the best. I'm sure it had a Smith chart but he sure as heck didn't know where to find it. And I wasn't going to buy a piece of test equipment from someone that doesn't know how it works. After all, how can someone like that guarantee that everything works?
Very happy with the clean 8753C I found later that evening.
Thanks for all of the replies!