went through the boards side by side and here are the differences I documented:
Remove:
17D - 053990 Custom
Change:
20J - Move from inbound position to outbound position
19J - Move from inbound position to outbound position
17H - Replace with KM62256BLS-10 (SRAM256K100N) and move to outbound position
18H - Replace with KM62256BLS-10 (SRAM256K100N) and move to outbound position
18F - Replace 056472 with 056371 (PAL20L10)
JP2 - From Long to Short Position
JP3 - From Long to Short Position
JP4 - From Long to Short Position*
JP6 - Remove Resistor and replace with 0Ohm Jumper in short position
JF7 - Remove Resistor and replace with 0Ohm Jumper in long position
JP10 - From Long to Short Position
Install:
14B - 24MHz Crystal
CN3 - JST NH 15POS Header
CN4 - JST NH 15POS Header
RA5 - A102J (RA1KX4)
5F - 054539 Custom
ROMs:
20F - 27c020
20G - 27c020
19F - 27c040
19G - 27c040
18F - GAL22V10
https://wiki.pldarchive.co.uk/index.php?title=Mystic_Warriors
6B - 27c010
1H - 27c800
1K - 27c800
3H - 27c040
22K - 27c800
20K - 27c800
19K - 27c800
17K - 27c800
12K - 27c040
10K - 27c040
2D - 27c160
1D - 27c160
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*Note: I looked a bit more at JP4... interestingly the factory position seems wrong, it's a 20F and 20G are 2M sized ROMs which should have JP4 in the long position. Though given that this is a smaller sized ROM it's entirely possible that either position will work so long as you're using the correct sized EPROM.
looking at pictures of some of these conversions I see some liberties taken like using 27c322s and other oversized ROMs which could change the jumper configs in places.