Need? No. Want? Yes.
From real life:
Science Results for Everyone
Maintaining strong muscles is a big enough challenge on Earth. It is much harder to do in space where there is no gravity. Calf muscles biopsies before flight and after a six months mission on the ISS show that even when crew members did aerobic exercise five hours a week and resistance exercise three to six days per week, muscle volume and peak power both still decrease significantly. Overall, the data suggest that current exercise countermeasures are not enough. The addition of a second treadmill and the Advanced Resistive Exercise Device (ARED) along with more rigorous exercise regiment are giving good results in preventing muscle loss and preserving overall muscle health.
-Effect of Prolonged Space Flight on Human Skeletal Muscle (Biopsy) - 08.15.18 -NASA
Unless your sleeper technology can make up for the atrophy of muscles that's normally seen in both comatose patients AND the atrophy seen in Active microgravity residents, the addition of artificial gravity would reduce this problem to coma patient level, which could be treated with neuromuscular electrical stimulation.
But neuromuscular electrical stimulation doesn't work for bone mass losses (Osteoporosis) as well, which is also another problem of microgravity. So your sleeper tech would also need that. Artificial gravity would make it a non-issue.
So need? No, your sleeper tech can adjust for the medical issues or have your travelers arrive skinny and weak. But you probably want it.
Whatever the source of the gravity, it should be about Earth normal 1G. Lower gravity would cause less stress to the body and still lead to skeletal-muscular mass losses (at a lower rate), and high gravity causes issues with blood pumping and stress to tissue. Sustained high gravity force can kill a human.