Colt stopped production of the 3rd issue (identifiable by the shrouded ejector rod) for awhile sometime in the late 80's, I believe, and then resumed again in 1992. Some call the guns produced in the 90's "4th issue" for that reason, but the guns are the same.
I've posted this several places before, so for those who've already seen it, please pardon the repeat.
I've used widely varying set-ups for my gun pics over the last few years. Some outdoors, some in the camera room with soft boxes, but most recently, on places like my desk, gun workbench, dining room table, etc. using available table and floor lamps and window lighting and small reflectors to create highlights on different parts of the gun.
Camera is currently a Canon 20D with 17 to 85 zoom lens. Always on a heavy tripod with electronic cable release. Usually ISO 200, f/11, about 1 sec. exposure or so, custom color balance. I spend a lot of time cleaning the set and the gun and positioning everything (lights, gun, camera) to get the look I want. I do some unsharp mask sharpening in PS and also adjust levels and color balance. What makes it easy for me is that I've been earning my living with a camera for decades.... so over the years I've picked up a few tricks. And I've been working with digital image editing on Macintosh computers (in Photoshop) for about 12 years.
Many of my most recent gun photos were taken on my workbench in my gunroom where there is a torchiere floor lamp in the corner and a north facing window. Some (like the 2.5" Model 19) are done at night, so they were lit by the torchiere floor lamp and a small desk lamp aimed toward the ceiling... which illuminates the upper walls and ceiling to the left of the gun... others (like the model 27, the 2.5" 686+, 586's, Detective SPls.) were taken during the day, so in addition to the floor and desk lamp light, there is also the additional north window light coming in behind and to the left of the guns - making for a mixed light situation (cool north skylight mixed with warm incandescent light from the torchiere). I use small white cards and other objects to reflect light into places where I want it. Sometimes I've used small flashlights to brighten up a selected area as well. Best thing you can do is spend the time with the camera trying a lot of different things... see what results and that will be the best education you can ask for. Lots of fun to play with all of this stuff.