I recently purchased my first CZ rifle. It is a custom bolt action with CZ stamped on the receiver but no model number. There is a 5 digit serial number on the receiver only visible with stock removed. Stamped on receiver near the CZ emblem is ( made in Yugoslavia).Barrel has no markings other than the caliber (6.5 - 284 Norma. This rifle was on consignment by a lady who's late husband built it. I would appreciate help or info. on using the serial# or pics to identify and age the CZ action.