I have a Revelation Model 110 (Marlin Model 81) made by Marlin for Western Auto. There is no serial number anywhere on the barrel, bolt, or receiver. Can anyone tell me, at least approximately, when these were made? There are 2 holes drilled and tapped in the left rear of the receiver, apparently for a peep sight that Gun Parts pictures, but does not have in stock. Can anyone point me to one? This rifle is accurate enough with open sights to neuter flies at 50 yards, but I think it will be even better with a peep. TIA for any info.