fred flintstone had a set of wheels like that! i remember an episode where barney was giving fred a hard time about his limestone colored wheels and they looked out the window to see dino hiking a leg on one. wilma wouldn't have that so she made fred go and get some shiny new wheels to break dino of his bad habit as dino was scared of his reflection. i wish my beagle and pyrenees were like that.
I have trouble believing those are factory for a TRD. IF I had to guess I'd say they were off a bare-bones basic work-truck Tundra or possibly some other base model truck with the same bolt pattern. The owner may have had aftermarket rims and had those as a spare winter set, then left those on and kept the nice ones when they sold it to you.
TRANSWHEEL Corporation - The Nations #1 Source For Replacement Wheels
With the above link you can find out about almost any Toyota OEM wheel all you do is enter your specific data and pull up OEM applications!
Never purchased anything from them but i use it for source info vs Toyota site, their pictures are kinda like black and white painted pics that have no color and hard to look at!