Is that a wide Gold Cup style trigger? If so, it could be a custom gun built on an old AMT Hardballer frame. IIRC they made some of they're guns with the serial numbers inside of a cut out like in your first pic. The Hardballers were all matte finished with laser etched roll markings that could easily have been removed when the frame flats were finished. Also, the thumb safety and slide stop look like AMT pieces that have been polished. All AMT frames and parts were stainless, the frame on that gun has obviously been polished but the color looks like it may have been hard chromed as well. That wouldn't surprise me because early stainless steel autos had problems with galling because the slides and frames were the same hardness, hard chroming them was an easy solution.
This pic gives a good look at the AMT Hardballer frame, safety, and slide stop.
Actually, the more I look your pics, it looks like the slide has a flat ridge which was also a feature of the AMT Hardballer, but the rear sight looks like a S&W revolver sight, a common 1911 upgrade back in the day. AMT made a longslide 10mm called the Javelina (pic below), I don't recall them coming in a regular 5" slide version so my best guess is that the gun you're looking at is a Javelina that has had the slide and barrel shortened and a bunch of other work done - checkering, sights, trigger, polished frame, hard chrome frame, some kind of coating on the slide, beaver tail, Commander hammer, and who knows what else. Check the bottoms of the mags, they're stainless, if they're original they'll probably say AMT 10mm on the base plate.
Found another Javelina pic that shows the serial number inside of a cut out like the gun in your photo. This gun's serial number also has a "J" prefix, same as the one your looking at. So, al of the evidence I can come up with says it's an AMT Javelina that's had a lot of work done to it.
Value? Whatever you're willing to pay. The last few years these old AMT guns have seen some collector interest but mostly the long slides. Obviously there is nothing original about this gun so the only value would be as a shooter
IF it runs reliably, AMTs were notoriously hit and miss. However, it looks like someone went to great lengths to work that gun onto something useable so I'd guess that any reliability and accuracy issue have been addressed. I wouldn't buy it without being able to shoot it. If it works well I'd offer something in the $500 range, it would certainly be worth that as a shooter, but without know any of the history or who did the work there really isn't anything else to add value to it. If I knew it ran and shot well, I'd give $500 for it, not much, if any, more.
Oh yeah, the work that was done on it was probably done a while ago, nobody really messes with those old AMTs anymore. Too many newer, less issue prone guns out there to build on nowadays.
Untitled by MattOphotog, on Flickr
