Do these mount at the factory rocker points without drilling?

Yes. These bolt at the existing factory rocker panel attachment points on your crew cab. No drilling, cutting, or structural modification needed.

What's the weight capacity on the running surface?

Weight specs aren't confirmed in the product data. Contact support with your specific use case and they can walk you through load limits.

Do I need to seal or paint the mounting bracket after install?

The brackets come pre-finished. Once bolted down, check the contact points where they meet the cab for any small gaps and seal with silicone if needed to keep water out.