Replaced my touchscreen -- works now, but I did it incorrectly.

I dropped my Pixel 2 and eventually my screen turned purple—>blue—>black. I ordered a new touchscreen from Ifixit and replaced mine. It works now, no noticeable issues. However, when removing the back of the touchscreen’s blue plastic wrap, a thin black (plastic like) layer came with it, I thought nothing of it and put the touchscreen in, tested it—worked—then glued it up. It has worked perfectly since. Afterwards though, I had my thoughts about that black layer, so I grabbed it and tried to see if it would come off the blue plastic wrap. It came off. I’m now thinking it must have been some sort of back shielding? IDK… I do know my device works, but I’m wondering if I greatly shortened the usable screen life?

I know this is somewhat of a difficult question, it would take really knowing how Ifixit ships their touchscreens to even understand what part i’m referring to. Thanks ahead of time.