You should be fine with aftermarket, the bolts on the frame are steel, so make sure you buy something that works well with that.
I highly recommend using a die to clean the bolts. It's super easy, quick and clean. This is the die you need (
https://www.amazon.com/gp/product/B0015UXIOE/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1), an 8mm - 1.25 size. You simply thread it on, once seated correctly, then use a socket and screw it down, then unscrew. You are left with super clean threads. It was the guys from American Trucks who gave me the suggestion.
Whatever method you use, make sure the bolts screw on easy, like finger twist easy. The specs to torque is only 15 ft-lbs, at least with the OEM boards and bolts. If you don't, you risk over tighten them. But the die above made short work of it. Unless you got a lift, trying to clean 18 bolt threads with a wire brush is a bit of a hassle lying on your back. The die is quicker and cleaner.