You photo matches the photo of a '33 tudor seat in the V8 Club 33/34 restoration manual.When folded forward the seat rides forward on runners secured to the floor. I would say you have stock seats in your car.- Dennis
According to the well know publication "The V8 Affair". These seats were used in 33 & early 34 when they were changed to a more contoured bucket style with a side on them part way through that year.