Overflow Removal HELP!!!!

[JJ Ligs]

I have a used tank that was stored in a garage in a fluctuating climate so the seal is shot on it. You can also tell it has been badly resealed before by just adding a ton of silicon on top of the old.
I started to remove all the old silicon to reseal it, which went fine on all the sides and seemed like an easy job, until I hit the issue I have now with the overflow.
I know that I need to remove the center flow tower to seal the tank correctly, besides the overflow is not the original glass overflow the tank was meant to come with. it was obviously a poorly made home job that it is cracked in a few spots and out of square.
Normally, I would not think twice to cut it out and replace it, BUT... This is something I have never seen before and it scared me enough to bring me to a screeching a halt.
This overflow has two thin pieces of glass that run along the inside of the overflow box. It definitely seems like they were for the original glass overflow but now they are using it as like a secondary brace for the plastic overflow to create an extra seal? I am having a heck of a time trying to remove this overflow and I an scared to go at it hard because I am not entirely sure about the glass pieces function.
ANY Help or input is much needed right now.

 

[DC Reefer]

can you share pictures? The overflows on two of my tanks have dual walls. The outside walls have slits in them that allow water from the lower 1/3 and middle of the tank to go through the overflow. Not sure if this is what your glass was for.

 

[JJLigs]

I have a used tank that was stored in a garage in a fluctuating climate so the seal is shot on it. You can also tell it has been badly resealed before by just adding a ton of silicon on top of the old.
I started to remove all the old silicon to reseal it, which went fine on all the sides and seemed like an easy job, until I hit the issue I have now with the overflow.
I know that I need to remove the center flow tower to seal the tank correctly, besides the overflow is not the original glass overflow the tank was meant to come with. it was obviously a poorly made home job that it is cracked in a few spots and out of square.
Normally, I would not think twice to cut it out and replace it, BUT... This is something I have never seen before and it scared me enough to bring me to a screeching a halt.
This overflow has two thin pieces of glass that run along the inside of the overflow box. It definitely seems like they were for the original glass overflow but now they are using it as like a secondary brace for the plastic overflow to create an extra seal? I am having a heck of a time trying to remove this overflow and I an scared to go at it hard because I am not entirely sure about the glass pieces function.
ANY Help or input is much needed right now.

 

[JJ Ligs]

can you share pictures? The overflows on two of my tanks have dual walls. The outside walls have slits in them that allow water from the lower 1/3 and middle of the tank to go through the overflow. Not sure if this is what your glass was for.

Sorry they were taking a moment to upload

 

[DC Reefer]

Look like support for the overflow box. I would remove all and then install the new overflow box. If not sturdy enough you could reuse the glass supports.

 

[JJ Ligs]

Look like support for the overflow box. I would remove all and then install the new overflow box. If not sturdy enough you could reuse the glass suppor

Okay but ideas on how to get it out I am super scared if I force it I may crack the glass or something.
I am very nervous about the resealing process in the first place as this is my first time doing it. this is my first big tank and I want to do this all the right way.

 

[JJ Ligs]

@vetteguy53081