Is it normal to have "data" in the extended block by mfg when it left the facility? Is this mfg data or user data? Can it be eraseable? How can you unlock it?

Is this 256M29EWL a flash memory part? I would suggest to go to menu on the left panel, pick Hardware Product (not FPGA developers), then look for forum discussing memory part under hardware products, you may need to scroll down the page to find the forum.