Need help deciphering date and facotry codes

Thanks. I'm trying to find an official altera document stating what the bottom side markings mean. If the 0037 is a date code, then it does not correspond to the date code on the top of the part. We recieved this parts and are suspicious of their origins. I would like to ind out exactly what they are, and if they have been relabeled or tampered with, I want to find definitive proof. The markings on my parts are as follows: