pdc replacement help
 

I was wondering if anyone had the updated part# for the pdc with the splash guard for a 2004 dodge 3500 5.9 diesel. I went to stealership to order new pdc for my truck and they just brought up the part# for my original one. I hate to replace it with one just like it as it will probably corrode too. I see several part numbers listed on factorychryslerparts.com such as 68005478AA, 68005477AA, and 68005476AA. They all have 2004 5.9 diesel listed as vehicle fitment. Not sure which one I need to order. My original Part # is 5026031AB.
If anyone knows a part # with the splash guard that would fit my application and has worked for them, please let me know. Don't want to order the wrong thing. Thanks.