I agree as to most upgrades not being able to fool an experienced Parker man,but many people are and were aware of Parkers as desirable and were and are not experts,just have enough knowledge to be dangerous and plenty of money to buy for their portfolio.Upgrade can mean anything that would enhance value,some of them relatively simple to do such as "Skeet" stampings on the barrel flats or presentation inscriptions.How many people that like Parkers can rattle off the proper serial number range for skeet guns?I think after 30-50 years of gentle use that a refinished/upgraded gun would be hard to detect from an original.
I think a good example of hard to detect upgrades are many of the lever action Winchesters.How many spurious "special feature" Winchesters started out as a clean,hard used gun that received the benefit of some expert metal work? Easy to spot if you have access to Cody letter
at the time the gun is offered for sale.Lots of upgrades are in collections that were accumulated by people not really gun people,but more interested in having something rare. The R.L.Wilson case of a few years ago is a good example.Money alone cannot buy you expertise,something the con men count on.
