Good find !
Those are STA Superlugs. They are bias ply.
However, they are 36.3" OD, so similar to the elusive XZL 9.00R16 / 255x100R16 tires.
There's a bit more info here : http://www.stausaonline.com/light-truck/superlug.html
If you can't get to Alaska, they are available elsewhere...
I would love to have a set, but don't think I can live with the non-radial costruction