UC3770A: IC UC3770A production markings

Hello TI officers.

My name is Jason from Abbott as Electrical Engineer. 

Our products use IC UC3770AQ from TEXAS INSTRUMENTS.

We find that there are two type production markings on the IC.

one is UC3770AQ - U61ZT1TW.

the other one is UC3770AQ - U9936- UR93602.

Might I know what is different between these two IC? it is same UC3770AQ?

And both IC have been converted to RoHS compliance or not?

Hope to hear you soon!

Thank you. 

Jason