Inground pool step gaskets

Just installed new inground liner, gasket kit i ordered is different than my original. Original had gasket under liner with plastic strip (with no gasket) on top of liner. New kit has plastic strips with a gasket attached, (came in 3 pieces).
1. Does this type strip need a gasket under liner?
2. Holes are not spaced same as old strips. New has holes 3" apart, old has holes 3 1/2" apart. Will this even work on my steps? Holes are not going to line up with holes in my steps.
3. Already filling pool, will i be able to put gasket behind liner if i use same type as original without too much trouble. I dont think using old gasket is a good option, its about 14 years old.
Thanks