GCVWR like Maximum trailer weight, is not a safety issue so you won't find it on most vehicles DOT safety data plate. Your manufacturer can give you the information as it pertains to your particular vehicle and if you have an owners manual it is often found there. Of course if your vehicle has no factory warranty on it, the information can still be useful but doesn't really apply to anything. It merely tells you what your vehicle warranty would cover when it comes to trailer towing. It is usually a good idea to follow these ratings anyway as they indicate what the manufacturer is willing to guarantee you can tow without damaging your vehicle. If you're paying for repairs yourself it would benefit you to have no more repairs than you have to.
Good luck / Skip