Hello, I am a new member and I hope to learn enough to purchase my own vintage Thompson Submachine Gun someday soon. I view some of the guns for sale on Gunbroker.com and came across this one today (I also saw it at a recent gun show in my area) ... https://www.gunbroker.com/Item/934992153 Did any these guns come from factory like this or were they always in a blued or parkerized type finish depending upon the model? Was the nickel or chrome plating an aftermarket addition and if so how does it impact value? Thanks!