At one time, the 36 was available with round or square butt, with a square butt frame. Then they dropped the square butt frame, but kept the square butt option in the line by making the wood grip square to fill in the space. AFAIK, they now do not have a square butt in the line at all for that model.
I have a 3" barrel, square butt frame that was my carry gun when I was a LEO. Great little gun, and the longer barrel gives a good sight radius. I have made believers out of the "snubbies won't shoot" crew by keeping all shots in a shihouette target at 100 yards, shooting DA off hand. Takes a bit of "Kentucky holdover", though, and more than a little practice. I know it's only five shots, and not a .454 Casull, but I never felt unarmed.
I always wanted one of the few they made with the square butt and the 3" heavy barrel with 1/8 inch sights. Never could find one at a price that didn't scare me off, though.
Jim