1) Sail numbers are the "serial number" of the sail. Other than that, they have no importance.
2) The "jib bag" is a snorkle cover for the jib. Since the jib cannot be removed without taking the mast down, the snorkle cover is raised over the jib with the main halyard when storing the boat mast up. You can try using a silicone spray on the zipper, but the teeth get brittle and break from UV exposure. It looks to be in rough shape.
3) The rudder is a "PCG" - a plastic rudder that's OK - better than the original ABS or Lexan rudders, but not at stiff as any fiberglass rudder and much heavier than the EPO rudders.
4) The tiller wrap was not unusual. Gives a good grip on the slippery fiberglass tiller, but it's a bit heavy. (That trampoline in the photo is whacked. It's been painted!)