Going to start this by showing the differences between the Endoskulls. One of the glaring differences between the T1 & T2 skulls is the port just behind the chip housing.
On the T1 Skull it has a grooved top and on the T2 skull it has a smooth top.
Both of the skulls shown are replicas, the T2 skull in the photo is a Winston gift skull.
All T1 & T2 Endos were Vacuum Metalized. This is the same type of plating that you find on model kit parts. It's very delicate and scratches easily. They were sprayed flat and weathered to taste. Photos of the original skeletons are coming.
I know there are videos of people telling you that they used triple chrome plate, that actually wasn't used until I made replicas for XFX in 1998 which later became HCG.
Some pics:
T1
T1
T2
T2