Nice truck is right.
It also has the big back glass on it, which if original, was an option (altho the sliding glass is not original).
My '62 GMC 4000 (very similar truck) weighed 8000. It had a longer chassis and a 16 Ft Flatbed on it. Dave seems to be pretty close, I would say that it weighs around 6000 to 6200, but bring it down to your local scale to be sure.
Top speed should be somewhere around 55 to 60 MPH, but if the engine has a lot of miles on it, I wouldn't drive it for long periods of time at top speed.
I like how the running boards and the fender fillers have been removed to keep the truck in line with the pick-up bed. I've never seen one of these trucks done that way and it sure looks good.
Keep us posted.
Bill