I bought two coin mechanisms from Asahi Seiko. They still make the same mechanisms that were used on the original Donkey Kong machines back in 1981. I called them up and ordered two. They mailed them out to me. They were not cheap.
If you search the KLOV forums there is always someone looking to place a big order with Asahi Seiko to get a discount or something. I think the original DK machines had the 740 mechs but I bought the 730s since I like them better and it's a minor difference.
The coin mechs come with special bolts to connect them to the coin door.
I bought the lock at Home Depot. I think it was five bucks.
I didn't realize that I would need special carriage bolts to hold the coin door to the cabinet and that really pissed me off. The coin door has square holes designed to hold carriage bolts which makes sense so that nobody could unscrew the coin door from the front of the machine and steal the money. Neither Home Depot nor Lowe's had carriage bolts small enough. The proper size is probably metric since this was a Japanese piece but I ended up ordering 3/16" stainless carriage bolts from Bolt Depot and spray painting the tops black.