Well, he called back and signed up, so for whatever the reason, my truck didn't matter. Or perhaps it did and it was the thing that pushed him over? Who knows... In this economy, I will take almost anyone... beggars can't be choosers.
And as for the cleanliness of my truck representing my work, I don't know about that. A coworker suggested that it was to see if it was a beater or not, if it was a personal truck and a beater, then I don't make much and am prone to bail for a better job, and if it was a company truck and a beater, then the company doesn't have the cash to maintain its fleet.
Either way, I don't think I have ever heard of this happening and is a certaintly a first for me. Perhaps one day I will find out...