YES you should go weigh truck 'camp ready'...you, fuel, passengers, backpacks, bags etc
Get your trucks real weights.....
NOW how much weight is left on that Rear Axle
Subtract actual rear axle weight from your RAWR of 4150#
Then subtract the hitch weight from that figure (70# up to 300# depending on WHICH brand of 5vr hitch you use)
Now you have a weight number left over that can be used to figure 5th wheel wet pin weight----22% of 5vr GVWR
Going to be limited to small light weight 5vr.
You WILL exceed trucks GVWR/Payload Ratings......but as long as you stay at/under RAWR good to go LEGALLY (Canada Laws do NOT pertain)
Personally when it comes to 1/2 ton trucks I prefer a 'bumper pull' cause you can get more trailer vs 5th wheel due to less tongue weights and being able to use a WDH.