Some These chassis were used in dedicated games.
For a short period of time.
Thats why the little board is on top and not used
it was for better Horizontal shift of Phase control.
I would experiment with the chassis for the game.
remove the cap on the bottom of the chassis ..completely
one reason your image is to wide as it is..
adjust the coil up so the image is narrow then adjust it out.
if it wont go completely out then change the pf across the tuning cap
or add to a .0047
the box cap c44 is for the secondary of the fly may have some image
issue because it parts of the video B+
the Box cap next to the yoke connector would have more to do with the
width..confirm its good too.
The most that would happen is the set go into shutdown as the peak to peak
level gets to high and cause the x-ray protect to disable the drive chip..
I dont believe this will happen, so i would experiment with these the coil
and retrace tuning cap.
compare with the what you have in the chassis with what the parts list has
and then make the proper tuning adjustments between the caps and the adjustable
coil..Good Luck!
https://www.wellsgardner.com/bom/P538.pdf