The TL:DR of this post will be that I do not think they drilled a whole in the bottom of the triangle gun ear to fish wire through to the legris banjo in GB1. I believe that was done during refurbishing in pre-production for GB2. Same goes for the Heat Shrink Wrap on the rectangle gun ear with the hat light and push button. I believe that in GB1, they let the wire hang from the push button to the banjo and at times covered up those wires with a matte finished tape of some sort, similar to what is seen on the side of the powercell of the hero pack (such as black masking tape). Please read further and look at the photos if you want to discuss.
With that out of the way, lets look at some photos!
The first 4 photos are of the Stantz pack. 2 Are from during production of GB1 and 2 are how it sits now in the UK. In both screen caps you can clearly see that the wire that goes over the gun ear to the banjo is just hanging there.
As it sits now, there was a hole drilled and the wire was fed through it. They also replaced the legris banjos with nycoil banjos and put heat shrink wrap around the hat light gun ear.
The next 5 photos are photos are of the Spengler Pack. You can see that throughout production, the bottom of those gun ears looks different.
Definitely bare wire hanging to the banjo.
You can also see that throughout production, sometimes the wires are covered and sometimes they are not.
They appear to be covered on the pack once it was put on display after filming concluded.
This makes me feel that, once again, they used black masking tape or some other matte black tape like gaffers to cover up the wires. As the pack looked during its time up for auction within PiH, the hat light gun ear also had heat shrink wrap on it.
The last 3 screen caps that I have of Venkman firing on slimer and the team firing at Gozer for the first time shows more of a mix of bare wires and possible matte black tape covering stuff up. When Venkman fires on Slimer, it looks like the wire to the banjo is covered but the wires for the hat light and push button are bare.
As they shoot at Gozer, you can see all the wands have the hat light/push button covered but you can also see some of the silver of the bottom of the electronics peeking through on the Stantz thrower, as I believe the tape is peeling off.
One last example of a pack that we see this bare wire to the Legris banjo but tape over the rest of the wires is on the OMNI cover photo.
After realizing all of this, I decided to cut off the heat shrink wrap off my thrower and replaced it with gaffers tape. This is what I feel they had done to the packs at least when they first fire at Gozer with all the wiring covered in tape.
Thanks for reading!