hi all ,picked up what i believe to be a mk2 .22 airsporter today.it has an opening on cocking breech tap and a walnut three piece stock.condition is good mechanically and cosmetically .stock has been refinished with polyeurethane varnish so i think i will strip that simpathetically restore it,what would the original finish have been? lacquer/varnish or oiled?.the blacked aluminium has also been refinished,but not so well so i think i will redo that as well, i think i have had good results before with plasticote black satin aerosol on this type of material.blueing is faded but nicely so, so will leave that alone.the gun has four grooves on the compression tube for scope mounts,are these still available?.the serial no is engraved not stamped and is GO19051.is it possible to tell the approximate age from this please..any info would be most appreciated,cheers greasemonkey..