What the heck is this part? Stamped 78R4

I'm not sure if this was related but I got the windows tinted in my 2023 Tundra today and tonight I found this part (pics below) laying on the floor mat under the passenger side dash. Gold star for whoever knows what it is and where it's supposed to go.

Has "78R4" molded into it fairly flexible polymer. I was first thinking it fell from under the dash but I looked and nothing made sense, then though like an endcap for a seat track but didn't seem to fit anything like that under the seat. I'm at a loss.

 

Pretty sure I recall seeing this when I had the door panels off a while back. Check out 68194B/68195B in this diagram:

 

Looks about right based on that parts diagram! I will look at that area of the door tomorrow. Thanks!!!

 

^ Team player..
Good catch figuring out the part...

 

I had my windows tinted today and I found the same part down the side of the passenger seat. 2024 Tundra. I went looking for the part and found this thread. I’m guessing you discovered that is was the part suggested by the above posters. Were you able to put it back where it belonged? Lynn

 

It looks like the cover of the seat bolts? R is the right side. Found it on my floor after I accidentally knocked it off with my foot…..I’ll look and compare in a little bit.

 

Thats what it is, had to put mine back on the drivers seat a few times.

 

Good theory as this happens to me at least monthly.
But I just went out to the truck and verified that is not the same part as the seat track end cover.

 

It's part of the molding around the window track in the bottom rear corner of the window. Just have to take the door panel off and set it back in place.

It's part # 68194B in the door schematic earlier in this post.

Easy fix, won't have to do it more than once.

If you look at your drivers side window you can see the top part of it at the base of the window, there will be a noticeable gap on the pass side door, that's where it goes.