Yes, different turrets. The Optimum’s turret was designed following the TTD, and was closely inspired from it, but they were different. I highly doubt the TTD would have been able to mount the same composite without some modifications. I don’t believe it was ever even planned to do so (although the TE article for it does briefly say “Additional reactive armor packages were to be added to the turret and hull to counter anti-tank missiles” – but what that refers to, I don’t know. If I remember correctly, the Optimum’s base turret is lighter and has more advanced composites, as well as the additional armour.
@NaasBotha24 I don’t know if the prototype had the 1020hp engine but this says the rest were at least planned to have it.