The tread pattern is Bar Grip. They're used by WWII jeeps and the like and hung around until the 70s. I've never had any, but heard that can be quite bad on the road in the wet, presumably as you'll be driving on that big slick area in the centre of the tyre.
I'm not sure if they're still made any more, so perhaps they're worth sticking on eBay to see if any military re-enactment type person would want them.