You can contact V&H and ask about replacing the pitted end caps, but after reading their warranty statement it appears they don't warrant the finish, and it also looks like they only warrant the parts to the original purchaser since they require a copy of the original invoice. This is the warranty statement:
"All of our exhaust systems are warranted against defects in material and/or workmanship for a period of 1 year. This does not cover finishes such as plating, or painted surfaces with discoloration or rust. This warranty shall be limited to the repair or replacement of the system, which may be proven defective under normal use. We will not warranty any system that has been abused, misused, improperly installed, or modified.
Dealers or distributors are not authorized to make dispositions binding upon Vance & Hines. We will not be responsible for any labor charges incurred in removing or replacing any system under warranty. All returns must be accompanied by a return authorization number and a copy of the purchase invoice. Parts being returned without a return authorization may be refused at our receiving docks."
Jerry