sasuke could see lee's movements, so he could imitate it yes.....
but 2 things......

1) seeing body movements is TOTALLY different than seeing chakra movement. It's not like sharingan can see the chakra circulatory system to see how naruto is molding the chakra.

2) after sasuke copied the movements, he still needed a month of training to get strong enough to imitate it. even if he sees the trick to creating the rasengan, he'll still have to practice for like a year to get the hang of it.