HI I  think the last time we made that boat was in 2007

For the seat pad that can purchased here: https://boutiqueborealdesign.com/products/whitewater-backrest

Instead of taping / gluing seat in place as they originally did back then, we now install this type of pad with these little plastic pinetrees. You could drill holes in the base of your seat and attach them with these. https://boutiqueborealdesign.com/products/pinetree-fastener-kit-includes-10-pinetrees

The Hip Pads are here: https://boutiqueborealdesign.com/products/hip-pad-kit-whitewater-includes-left-right-hip-pads-6?variant=28063766937684

For the Thigh Braces - they can purchased here: https://boutiqueborealdesign.com/products/suregrip-wihtewater-thighbraces-includes-2-roto-thighbraces-2-neoprene-covers-hardware-4

Hope this helps,