Don't think its a true K30.
From the side shot, the lower frame rail doesn't sit low enough to be a one ton.
Also from the side shot, the rear shock is outboard the frame rail. One ton shocks are inboard.
No roof marker lights or tailgate lights is another clue.
Hard to see from the pics but I'm not seeing the rear u-bolts with the threads pointing downwards.
I think its a K20 with swapped in D60. Seller needs to provide a VIN to make sure.