I am thinking of getting a set of OEM mud flaps off ebay.

Do they require drilling?
Do they actually help keep the truck clean?

It is for an '09 quad cab

here are a couple of sets...
http://www.ebay.com/itm/2-SETS-FRONT...db068b&vxp=mtr

http://www.ebay.com/itm/2009-2010-20...82f854&vxp=mtr

 

Yes they will require drilling.
Yes, they help keep mud off of the fenders.

 

The OEM mud flaps do help keep the lower panels clean and also help prevent rock chips in the paint along the lower sides also. Front mud flaps will also help keep your side steps clean if you have them.

I had to drill the mud flaps bottom hole to help align it with the bolt hole in the truck, everything else lined up. You will have to remove the plastic piece that is bolted in place where you will install the flaps

 

Don't do it unless you are going to put a 3M or equivalent film under them. They carve into your paint. Try these.

https://dodgeforum.com/forum/4th-gen...mud-flaps.html

https://dodgeforum.com/forum/4th-gen...mud-flaps.html

 

I installed the same OME mud flaps on my truck, but I didn’t drill into the truck. I just used what was there and have had no problem.

 

I installed the same ones on my truck. I didn't bother with drilling, the pre-drilled holes seemed to provide a tight enough fit on the flaps to bother with messing with drilling one more hole in each one.

 

I didn't have to drill any hole in mine. Ther was an extra hole in the flaps,but its not needed.