Quoted from Lonzo:My mountain in the upper left is broken in half if anyone knows where I can get one.
Try asking "arakissun". I think he did have the mountain for sale at one point in time. Really old post but here:
https://pinside.com/pinball/forum/topic/selling-pinball-parts
Quoted from Axl:My treasure chest is worn down to the insert. Wish someone would make a decal for it.
Can try printing your own transparent "slide" / "water transfer" decal based on the image here:
https://pinside.com/pinball/forum/topic/decals-insert-gilligans-island
Not sure where you can buy the transfer sheets, but you print on them, then immerse it in water to slide it off the backing. Like those that came with the plastic car models back in the day.