As I understand it the OEM ones are discontinued. There may be some still on the shelf, but that's all. I can only speak for the strength of the OE ones, they're plenty heavy for anything a 1500 has any business doing.
The aftermarket copies are a whole lot lower price.. I'd imagine they're just as strong - OEM and aftermarket both are going to try to make things as cheap as they can get away with and one of the aftermarket ones even claims to use the original forms (likely the same manufacturer, now free to make them for the aftermarket since the OE channel is discontinued)
When I got mine I bought the blackout panels with the hole cut already, that part was something like $25 for the pair. I figured the cost wasn't out of line vs. the time it would take cutting my own & since my truck was brand new I wanted to keep some of that new/flawless look on it for a little while.
But later I put an aftermarket bumper on and made that a moot point.