Door panels pulled for speakers and this left behind (Pic)
 

I pulled my door panels today to replace the stock speakers. Everything went pretty easy. My only issue was after pulling the truck out of the garage I found these on the floor. Not sure if they're from the front or back or maybe one of each. Obviously I never saw them fall out to begin with. Before I have to pull all of them again to find out which doors and where exactly they would go I figured I'd ask for some help here first. Looks like a little rubber plug or boot. Any help would be appreciated.
Thanks.
2017 f150 xlt.
https://cimg4.ibsrv.net/gimg/www.f15...fafdc928a1.jpg

They might just function as quiet-ing spacers, for lack of the proper term.

There's a "finger" on the door pannel that they slip over. Mine fell off too when I replaced my speakers. If you look into the hole of the rubber it should have a + or x grooved into it from the plastic part it was pressed over/onto.

Thanks for the replies. Thankfully these panels are real easy to pull. Will check today.

Honestly, they are probably bolt covers for studs when they ship/assemble the door to prevent workers from getting cut/panels and parts from getting scratched. They get brushed off the studs when it is time to shoot the nuts for the bolt, and sometimes they don't fall all the way to the floor if they fall into some place where they can get caught.

They are guide bushings. They usually stick pretty good, but Tommyboy nailed it. They stick in the hole in the door, then fall out as you are working on it. When you have the panel off again, you will spot where they go pretty easily.

Thank you all.
acdii - Do you know if there are more than 1 per door? When I pull the panel(s) again will I see others?
Thanks.

That I don't know, havent had the 15+ door panels off. The 14 I believe had two, one on each side near the top, just above latch level.

https://cimg7.ibsrv.net/gimg/www.f15...a1aaa34a69.jpg
If i'm not mistaken, I believe they go on the + looking "finger" just to the right of the FR label on this picture.