None mechanically. My shooting partner is a retired Judge- very fussy about his double guns- He has two older Philadelphia ejector grade Fox doubles- when he acquired them (from an estate when he was an attorney-they often find the best guns that way)I saw them, shot them, found them to be A-OK- not so for him- had them reblued, re-case colored, new pads, wood refinished-
Sorta like the Fox Sterlingworth 12 Field and Stream shotgun editor Phil B. wrote about a few years ago- bought it from Iowa Scheels at I believe $1800 (must have had ejectors and single trigger to bring that amount??) and had it refinished to "like new"- and then remarked that it would be worth just about the $1800 he spent to buy it after all the work, should he wish to sell it--
My friend was concerned about the wood to metal fit at the tangs, the fit of the pad to the buttstock, one screw in the trigger guard bow didn't line up with another, etc- He also wished he had ordered the double trigger version- none of these "nitpicks" would keep me from owning that gun (if I had the cash) as it fit and balanced perfectly for me-
I won a Ruger 12 O/U Sporting Clays at a PF Banquet about ten years ago-I assembled it, and it felt like a 2x4 in my hands. I am NOT a clays shooter, much prefer side by sides to any O/U (unless you have a Boss or Woodward 20 bore at $3000 you want to sell)so I sold it at cost to the Banquet Chairman and took home a check instead of the Ruger for my $20 raffle ticket-to each his own!!