For a clearer picture of models, look here: https://www.gregmarsh.com/MC/Norton/CommandoID.aspx It almost certainly began with silver barrels. Unless the battery box and air cleaner where change it's not a "A". The only real detractor on price, and it's not much of one, is the gearbox serial. To me, if the engine and title match on a pre-75 it's good enough, the gearbox too is gravy. So, if I wanted it, and I was standing in front of the seller, I would offer less with cash in hand and only peel of the extra thousand if I had to. But in that price range, they sell easily so don't mess around if you really like it.