LM318: LM318N/NOPB marking consultation

Hello, 

It is difficult to say however the device has been around since 1998 (26 years) and was developed my National Semiconductor prior to the Texas Instruments acquisition. It is possible one is an older manufactured device and the other is newer. Were both acquired from our authorized dealer list? If so than there should be no issue with performance. 

https://www.ti.com/ordering-resources/faqs/purchasing-online/authorized-distributors.html

Best Regards, 

Chris Featherstone