hi, you can see the MSL on the moisture barrier bag - there have label with mSL.Two years ago , I check all components in our stockk and insert the data in the ERP.For any components I find the MSL in their data sheet.About 20-30 component I cant find any information and ask the supplier.Now , I have MSL for all IC,transistors, diodes, leds...As a result of this project, now I have not any defects with LEDs - they are very sensitive .
(http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=66079)