See link below.
By maker information.
Mainly in the stock
Unless it is marked Trap or Skeet, it is probably a field gun. Skeet guns were choked appropriately, as well. sales@countrygunsmith.net
With a field shotgun, the target is placed directly behind the bead. On a trap gun, the target is placed above the bead for better visibility. That is the main difference. Also, the comb is elevated on a trap gun and the stock and butt plate are sometimes adjustable on a trap gun. Trap guns are also heavier to reduce damage to the shoulder due to repeated firing. Trap guns sometimes have ported barrels to reduce jumping of the barrel. Any highly shotgun with a wooden stock and replacable barrels can probably be converted into a trap gun. Just buy a trap barrel and replace the barrel. You can also port the barrel or have the stock cut out to make it adjustable. Honestly, no modifications are needed to a field gun, as long as it is a decent gun. I shoot a field gun for trap and I do just fine.
Trap shotguns are only used for trap shooting and should only be bought if you are really into trap shooting (or have too much money =] ). Field guns can be used for both field and trap applications. However, field and trap guns aim differently. Trap guns are easier to use for trap, and I'm not sure on the other way around. My advice is to by a field gun to use for both uses. That's what I did, and I get great trap scores. If I had an extra $2 or 3 thousand, I would by a trap gun because they work better for trap, but I don't =).
Franchi LF-57 is an Italian submachine gun manufactured by the Italian gun company Luigi Franchi S.p.A.
Franchi S.P.A. of Italy.
Gun shop, gun show, egunparts
I would say yes. If it is a trap gun, then it will more than likely be ideal for trap shooting. Honestly, I wouldn't buy a trap gun until I was sure that I was commited to trap shooting, because you really can't use a trap gun for field applications. If you are a beginner, I would just use my field gun that you probably already have until you get the idea and figure out if trap shooting is something that you like to do. Also, if the gun that you are talking about is a pump, then I, personally, would consider a breakaway. That's just my personal preference. I've never used a pump shotgun for trapshooting, but if I did, I'm sure that I would get tired of the pumping into my hand. A breakaway or semiauto is just so much easier to use. If you're going to be involved in trap shooting, then by all means get it if you want. Have fun!
50-100 USD
Look on auctionarms.com or eBay