Apparently the Remington without the normal trigger and trigger guard must have been designed for shooting with the shooter in a prone position on his back. The forward part of the barrel extending just beyond his feet, of course you have to elevate your head and neck.
Could well be. Search for signs of a sight having been mounted on the back end of the comb of the stock.
What caught my eye was the second rifle - an extremely bullish bull-barrel. What does it weigh?