If the pcb's are working it is worth about what the entire game is worth. They are a pain to work on and the roms don't work right outside of the original game. The end of the jungle scene will not show up in mame but will work with the original hardware. Many of the problems I have found so far are with the custom sip chips and are very hard to find (working). I have seen where there is a custom made board that goes into the sip slot for mixing the sounds and am currently working on a socket for replacing and testing the custom sips. I have 8 1/2 sets of pcb's and only got one set working 100%. The others seem to have other problems some very severe and others just a few sounds not working. Many of the sound problems I have found were NOT the sound board but the signals to activate the particular sound. The 384 khz crystal is not real easy to find buy you can use a 400 khz crystal with not much difference and I think mouser has them.
I would get the game but only if the pcb is working and would not consider it if the board set is dead. I do have a few boards that are quite different on the main board and they are the earlier versions that have only one big sip (SINGLE IN LINE PACKAGE) in one corner of the pcb, normally there are about 3 of them type chips there.
If you do decide to get the game there is some things that should be done to keep quarters from dropping onto the pcb. They get under the gun assembly and fall on the pcb. Drinks is another thing that seems to get spilled on the game, it gets used as a table quite a bit, and a splash guard is another must.
Not much is really a hard fix for that game except for the pcb's.
Good luck with the project, I am still working on mine and hope to drag the working one to Magfest.
Oh, and mine is missing the gun recoil motor and am considering using a portable air compressor for that motor. It looks just about the right size to fit in there and it is DC.