if the right middle plastic looks weird to you,  you are not alone

but that clear end is their on the original table

https://www.ipdb.org/showpic.pl?id=985&picno=31223&zoom=1

I ncluded an extra image texture without the clear part

go to layer 4 select the primitive and change it.

Back Wall LEDs

the backwall LEDs are turned on by a generic 3 digit matrix and only turn off when the GI lights turn off.

the pattern will more then likely not match the real machine.  I have no idea how the real machine works.  They are not mapped to a rom ID given that PINMAME does not generate any other Light IDs then what its on the service manual.