Have you tried repairing it?
https://pinside.com/pinball/forum/topic/repairing-plastic-playfield-features-onsite-vids-guide#post-3651945
OR you can just buy it from this online store.
https://littleshopofgames.com/shop/playfield-plastics/playfield-plastics-single-plastics/indiana-jones-lost-plastic-31-1773-lost/