LM74: lot trace code manufacturing dates

Part Number:LM74

Team, my customer is having issues with LM74CIMX-3/NOPB variation across temperature. 

They have three different date codes of parts, bought at our authorized distributors over last 10 months:

• 82LD
• 82LC
• 6762

I can't seem to find on ti.com what dates and manufacturing facilities these LTC's correspond to. Can you help? 

Thanks

Viktorija