A GMC Canyon does not have a lot of payload. You will put a camper with a long overhang on the truck.
The camper CoG will be at or behind the rear axle.
Depending on where exactly, all the camper weight will go on the rear axle, and some additional weight may even be transferred from front to rear. You can expect to exceed the RAWR. At the very least, be aware of the actual weight on the rear axle and the load capacity of your rear tires.
Where do the 520 kgs come from? If that is the dry weight stated on the camper, it usually excludes any and all loads such as water, lpg, your belongings, often even the camper jacks. The actual weight ready to travel will be a lot greater.
Add to that the weight of all passengers and whatever else you are bringing, like bicycles or sporting gear.
You can add up specified numbers as much as you want, only a scale will tell the truth. If you get the rig, weigh it - ready to camp. It might be a good idea to weigh the empty truck beforehand. Get the axles weighed separately. You can overload, but you need to know the actual capacities and weights.
Also, you are looking at a 33 year old camper. There is a significant risk of major structural damage (water leak, wood rot). If you do not know how to spot the telltale signs, bring someone who does. If the camper was in dry storage for some time, everything may be dried out now, but that doesn't mean it can not leak when you start using it.
2014 Ford F350 XLT 6.2 SCLB + 2017 Northstar Arrow