It really depends on how they fit. I bought aftermarket endcaps and will probably spend more than they cost to make them fit right, so I may have been better off waiting to find some original pieces, and paid the extra $$.
I just went through this with replacing quarters - after fitting the first one, decided to go NOS for the second one. It cost a lot more but I saved $$ because the repop quarter cost so much trying to get it to fit. The NOS quarter fit perfectly.
Go NOS or used wherever you can - its cheaper in the long run.