19 wk old sleeping on tummy

[Nanoon]

DS2 (19 wks) mastered rolling on his tummy during play about 6 weeks ago but tonight for the first time he has rollled over once put down in his cot and is fast asleep.

Should i turn he back over or leave him where he is? He can't yet roll from front to back but can lift his shoulders and upper chest off the floor.

Thanks

I would roll him back once but if he does it again leave him he will only roll over again if he likes sleeping on his tummy