Holes under fender extension - how to cover?

[RunsWithScissors]

What have you filled this hole with? I added screws with black plastic caps to the small nutserts, but can’t find anything right size to plug the larger hole. I bought some plastic hole plugs but they were just a smidge too large. Does anyone have a specific link to something rubber or plastic that actually fits?

Bonsicoky 4 Pack 1-1/4 Inch - 32mm - this is what DIDN’T fit

 

[TheBoogieman]

 

[AndyG]

What have you filled this hole with? I added screws with black plastic caps to the small nutserts, but can’t find anything right size to plug the larger hole. I bought some plastic hole plugs but they were just a smidge too large. Does anyone have a specific link to something rubber or plastic that actually fits?

View attachment 649972
Bonsicoky 4 Pack 1-1/4 Inch - 32mm - this is what DIDN’T fit

View attachment 649971

I think the name is Great Western Products- they are a seller of various hardware items.