what is this?

so i went to roll my window down yesterday and it just fell into the door. i took the door apart and found the problem.. i also found this and was wodnering what it was... the square patch type thing inside the door.. theres the first one, then another one deeper in the door, with like an oval thing half in it. is this exactly what looks like, a patch?? from a body shop fixing body damage, or is it somethiing else? i went to peel it off for about 2 seconds then had second thoughts...

http://i2.photobucket.com/albums/y31/jakegday/100_4485.jpg

http://i2.photobucket.com/albums/y31/jakegday/100_4486.jpg

The factory puts those in various places to reduce noise. Stops the body panels from rattling and wobbling. Yes it does work. There should be more of them in the trunk against the side body panel. If you remove it it won't add much noise but it doesnt hurt to leave it there unless you are in an area bad for rust as rarely moisture can get at the edges and promote rust under it. That too is rare.

thank you for the response. noise reduction is what everyone else ive asked has said too

A more infamous example of that is found on the new Camaro. As an afterthought, weights were "glued" to the brake calipers to deaden the harmonics and prevent chatter. It seems that engineering is a lost science.