BROWNING 20 gague Automatic

I would really appreciate it if someone can give me their best guess on value and date of mfg on shotgun described below. Embossed on butt plate (rubber) is BROWNING AUTOMATIC and letters FN. Right side below bolt lever is letter W a crown symbol then a PV and another small symbol of somekind. Left side of receiveron bolt housing is written TWENTY below that is a circled R under that is'BROWNING' then an engraved image of a man. Has a gold trigger and beautiful scroll work on both sides. It is an absolute beautiful shotgun. No marks blemishes or scratches and the bluing is perfect. In my mind I think that it should grade 98/99 percent. SN #2Z628XX Please some one help me out.