The floor is factory SS in 1962 Convertble with factory welds on the brackets.
The SS brackets with the long brace is 1962 only. Only 1962's had the long brace under the brackets into the back seat area. 62 SS floor brackets will work in 63 and 64.
I had to replace the front stud (closed to the dash) since these pictures were taken. Part of the stud had been broken off and I hadn't noticed it. The interior is still not finished, working on the dash, motor etc.
I have added(body shop guys did the welding) SS bucket seat floor brackets to 62's and 63's that did not come with SS bucket seats or the floor was replaced. In the 63 SS one we used repro floor brackets (they did not fit good on the floor). The repro brackets had to be rasied in the rear to fit.
The 62 SS was the original SS brackets added to a reproduction floor pan. This 62 SS 409 Convertible is in my garage under restoration (it belongs to a friend)
You need to mount the SS brackets to the seats and mark/weld tack weld to the floor while still attached to the seat.
Finish the welding after they are tacked to the floor.
All so the seats will fit correctly on the studs after the welding.
Paul
Here are pictures of my friends 62 SS convertible with the factory SS brackets added to the reproduction floor.