Yours is a nice example of what I'd guess is a mid fifties Greyhound. There were a few models with the wooden body available, some with stake sides, some without, some with tractor tread tires and even dual rear wheels. I have a Hamilton Greyhound wagon with hubcaps that have a "B" stamped into them. Just like all the other "H" stamped ones I've ever seen but it's a b not an h ? Was a flawed or incorrect die used ? I've also got some with the entire name Hamilton. Some of the older Radio Flyers have "Radio Line" stamped in them. You've got a nice wagon there.