Could this be thrips?

nope... and i doubt you see those blemishes on newer leaf growth... those initial 1-3-5 finger leaves are more prone to blemishes in my experience and probably just genetic. Watch that internode length.. if too tight, raising light a couple inches will help nodes get a little more spacing.... or more light if it stretches too much etc etc... pictures are decieving, so don't take what i percieve too seriously.. but looks a bit tight. -- could just be that 3-finger leaf is bowing upward trying to maximize it's light, too.