I JUST FOUND MY 870 WINGMASTER THAT MY DAD GAVE ME NEW IN THE MID 70'S...I NEED HELP ON DETERMINING THE VALUE. 28" VENT RIB WITH MODIFIED CHOKE, 2 3/4, SERIAL # STARTS WITH A "T" AND ENDS WITH A "V". THIS GUN IS ALL ORIGINAL JUST LIKE WHEN I TOOK IT OUT OF THE BOX. NO RUST, GOOD WOOD, OVERALL...