Yes, it is a Chouinard. Actually it is mine being aired out for a trip last year after sitting in my gear closet for a couple years. It was my main shelter for over 20 years, but I have lighter options these days.
The side stake-out points effectively make it an eight sided-shelter, instead of four, like the first picture. This probably reduces the wind load by maybe 50% or more. I am sure some mechanical engineering expert here can enlighten us. If the side stake out isn't done correctly, you can unwittingly turn it into a 4 sided shelter, which isn't optimum.
Without stakes or the included pole, it weighs around 2 1/2 lbs, quite light for the 80's. I usually used my hiking staff as a pole, put would need to find a rock to raise it high enough. Never had any problems with it in any wind, and it withstood its share of strong winds. Since I only hike solo, spindrift was never a problem, since it is so palatial inside, I could move to the other side. A pole in the middle can be an inconvenience. It is subject to condensation, though. One night it got down to 17F inside the shelter and the next morning all walls where covered in a sheet of ice.
Probably my favorite shelter of all time.