The manufacture date can be verified by the serial number found on the product. The first four digits after "SN" determine the year and week of manufacturing date. For example:
"4719331822101 SN082540084966" represents the 25th week of 2008
Check the manufacture date, then check here http://www.gigabyte.com/products/product-page.aspx?pid=4002#bios
what BIOS version was available at that date. That would most probably be the board's BIOS version.