All depends on the depth of the hull, weight in the boat, weight of the humans and the experience you are looking for. It' s not uncommon to see 4 people on the front of a 1648 with an elevated deck if it's a deep enough boat and the humans are smaller. You gotta watch your movements and be prepared to swim.
3 people my size on the front of an 1860 Alumacraft (shallow hull) and we were taking water over the front end if there was much of a ripple.
If you want a boat that is comfortably stable in rough water with 4 average size people on it I would get a bigger boat. If you are looking for a cheap option to get you on the water and you have decent balance go for it.