Just recieved this today from CDNN Sports.  PreOwned Beretta 92FS considered by them to be in "very good to excellent condition."  Not sure if it's a former law enforcement gun or not.  Regardless, it's really nice.  There's one nick in the bottom of the frame on the left side under the serial number.  Aside from that there is only very minimal holster wear to mention, mostly on the trigger guard.  Very well worth the pice I paid.  The best part is that it came with a Hogue grip already on it.  I was going to buy one, but this will save me some money, so as far as I'm concerned a good deal got even better.  I haven't shot it yet.  Just field stripped it and cleand her up.  I'm going out to a friend's farm tomorrow to put some rounds through it.  I'm sure I'll have more to add after firing it.  Depending on how I like the trigger pull I may or may not order a D-spring.  Wanted to fire it plenty "as is" first.  I hear these guns will make you turn your back on other guns, make you not want anything else, become your favorite, yada yada yada.  I love my Glock, but I do hope I love this gun as much if not more... as everyone else says I should.  Ok, enough talk, here's a couple pictures.

http://c3.ac-images.myspacecdn.com/images02/25/l_c3d23b63ded34ceebb9dbf0d1527be3e.jpg

http://c1.ac-images.myspacecdn.com/images02/7/l_51cda22d18cf4439a0f2f54cd42135f0.jpg

Figured I had to take one with my "evil black rifle"

Congrats on the gun!    

I'd bet it was a LEO trade-in based on your description.

As for the mainspring, I would indeed swap in a DAO spring as well as replace the recoil spring & trigger return spring. A new recoil spring for $12 or so is cheap insurance against a battered frame, IMO.

My .o2

Congratulations on a very good handgun purchase.  One can never go wrong with a Beretta 92, new or used.  If you do decide to purchase a Factory "D" hammer mainspring for your Beretta, the part# is "UD99001" and the cost from Beretta USA is $2.50 per.  Pickup a few spare recoil springs at the same time ($2.50 per) and you will be good to go for decades to come.  I've spent close to twenty-years trying to "break" my Beretta 92F and haven't succeeded yet!  Hell, even the slide hasn't broken and smacked me in the face.  I must be doing something wrong!  The Beretta 92/M9 is one tough machine.  

Good luck and enjoy your Beretta.  A true companion to your 20' A2 rifle that will never let you down.