Why would a simply homeowner keep a "stock of outlets"? You made it seem like you had cases of them.
It does sound like the doesn't it.
I bet he probably means he has a few of the regular/non TR receptacles on hand. I know I do. I keep my "stock of outlets", or usually about three of them, in a box in my basement, along with a variety of different colored switches and cover plates, for repairs or additions around the house.
I like to keep a few of these things on hand because my house was built in 1955, and although the previous original owners did do some upgrades over the years, there are times when a receptacle or switch needs to be replaced because they are becoming faulty.
Since most of my receptacles and switches are white or "cream" colored, I like being able to just go down into the basement, grab what I need, and make a repair on the spot. Then if my small supply runs low, I buy a few more when I go to HD or Lowes.
Jim