Gdawgs is right. Different metals may have been used for those pins. They will take to the finish or oils (because if porosity) differently. It's nothing to worry about.
Gun repairs can be First-in, First-out. You want to return the gun ASAP to the customer as possible. If you hit a delay (like waiting for a part or for a jig to be free), then the serviceman moves onto the next gun to keep busy. If there is a heavy workload, it can take a couple of months. I waited over a year for one reputable gunsmith to reline a revolver barrel.
Gun repairs can be First-in, First-out. You want to return the gun ASAP to the customer as possible. If you hit a delay (like waiting for a part or for a jig to be free), then the serviceman moves onto the next gun to keep busy. If there is a heavy workload, it can take a couple of months. I waited over a year for one reputable gunsmith to reline a revolver barrel.