DS did this at about the same age and immediately seemed much more comfortable! And like you say he ends up in all sorts of different positions when he's in his cot now-it's very cute! Sadly he hasn't read the 'sleep in till 7am' bit of the manual...!
Yes absolutely fine if your LO has got there himself. My DS (also 7 months) is now frequently found in the morning right down the bottom of his cot, lying sideways across the width of his cot either on his belly or his side.
He too seems to sleep better/more deeply now his can till around like this.