Its bluing looks original. As posted above it dates frome the start of stamping MADE IN USA to the discontinuation of the mushroom extractor rod tip. That is such a narrow range that the specific year would only matter to very few people so there's no need for its serial number.

Unlike plastic fantastic gotta have 'em panic pistols, IMO, it is a luxury discretionary item that is primarily of interest to, (how to put this politely?), stunningly hansom senior forum members with wash board abs. As their stored funds plummet into the abyss with the rest of the stock market so will its value. Are you asking us to speculate what it might sell for this week, next week, the week after or ...