I was confused before, mainly on how the GCVW (Gross Combined Vehicle Weight) is figured to determine if a CDL is required or not.
I called my states DOT office and they cleared the mud up a little.
Your GCVW is simply calculated by adding the GVW "Gross Vehicle Weight" of your truck and the GVW of your trailer together.
So with a 14,000 GVW trailer, the biggest truck GVW you could have is 12,000 without a CDL.
I'm not sure if it matters for CDL requirements what your truck is tagged for or not. The lady at the OK DOT office told me the numbers are figured off the GVW number listed on the stickers on the truck and trailer. She did not mention anything about tags. I specifically asked this, because for some reason my trucks sticker that list weights is missing (I think it's been re-painted). I'm not sure how Mr. DOT would determine my trucks GVW, since there isn't a sticker on my truck anymore.
In Oklahoma "and many other states" the CDL requirement does not apply to farm tagged trucks. Farm tagged trucks can pull ANY weight combination without a CDL, as long as they meet the farm tagged requirements.