M7040 rear light question

[Dave M7040]

I have a M7040 with ultra cab about 2 yrs old.
One of the yellow signal lights on the rear fender had a bulb burn out.
When I removed the lens to replace the bulb I could not tell if there was a gasket between the lens and the lamp housing.
Pieces of a small round rubber like material came out when the lens came off.
I got the parts diagram from Messick's but it did not show anything but a complete lamp assembly.
Dave M7040

 

[gwdixon]

Try taking a look at the light on the other fender.