This may or may not be where the serial/model number is on that certain firearm but, open up the chamber and look on the small flat piece of metal just in front of the opening towards the barrel end. There 'should' be some numbers on that plate. This will be the serial and the model number of the firearm.
Revolvers are not lever action firearms. Sorry- can you rephrase your question? Lever action firearms are most often rifles, rarely shotguns. A very few lever action pistols were made, but not revolvers.
A good candidate may be the Starr Model 1858. This was a ball and cap revolver. With cartridge firearms, Forehand & Wadsworth made a .32 revolver inn what we would today recognize as a "double action: revolver. However, there were earlier "double action only" pepper box pistols.
The action is the heart of the revolver
100-500 USD or so
I might be able to help you. I just acquired what I think is a 32 young America double action revolver. I was once my grandfathers. It is not in the best shape. I will know more about it tomorrow when I take it to a firearms dealer. I will post the picture later.
Firearms International was an importer, now out of business I believe. It is unlikely that they would have actually marked the gun with their name before these markings were required in 1968. There are probably other markings that may identify the actual manufacturer. Double Action refers to a revolver mechanism and I have no idea what you mean by a doubleaction trigger on a rifle.
100-500
Double action revolver
Try gun shops, gun shows, want ads
The "Pink Lady" model is a double action revolver. They do not have, nor do they need a safety. The safety ia in the long, relatively heavy, trigger pull.
Old gun catalogs from the 1960s
Depends on the revolver