Usually original GM parts are a better solution if you can get them.
Repro stuff is made from thinner gage steel which has a tendency to not hold its shape within tolerances once the stamping process is finished. GM used certain gage steels for a reason. Pacific rim repro stuff is made from thinner material to cut corners, save money, which usually translates into more time spent on fit and alignment of body panels.
Original pieces may be more costly but could easily save you time by aligning properly without having to evoke the old adage, "Beat to fit, paint to match".