What is the approximate value and manufacture date of a Browning A-5 with serial number 78xx with a plain barrel and burled walnut stock?

This serial number would indicate a gun made in 1904. To be sure that this is not an early gun, you can check the barrel. If the gun was made in 1904, the barrel would be stamped: BROWNING AUTOMATIC ARMS COMPANY It is probable that your gun is more modern. Check the gun for a letter above or preceding the 78xx number. The complete serial number would be required to answer the question. Thank you