The red arrow is pointing at the right front corner of the slot.
CHE Tang.jpg
Below the tip of the arrow one can see the whole straight front edge of the slot.
On Remingtons they used a different trigger spring and the head of the stock was solid on the no safety guns. I've never seen the inside of a righteous Fox or Parker Bros. no safety gun, so would like to hear from some gunsmiths/stockers on what they have observed on the inside.