Nice looking game!
On some pinballs you can disable the "replay knocker" in the setup menus. Otherwise check the wiring at the knocker coil lugs. Sometimes the coil is in the backbox, sometimes in the main cabinet. That game is vintage and will have a real knocker, not a virtual one that's emulated as a sound effect.
If the coin mechs are present and intact, it's usually just some fiddly adjustment to get them working again. They have springs, weights, and a leaf switch. If the coin is the correct weight etc. it passes through and trips that switch. If everything seems to be right, you might just need to clean the contacts on the leaf switch. Slide a business card or piece of manila folder between the contacts, hold them together gently, and move the card in and out a few times.
Is that right flipper stuck?