Yes
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As previously stated, Yes. It can. But it would probably hurt your hand quite a bit. There are usually mechanical functions happening under the grip. The hammer spring/strut assembly is usually there. That covers 99% of most revolvers/auto loaders.
Glock and other polymer framed "striker fire" guns generally don't have this, but the grips are usually not removable anyways.
Impossible to answer without a DETAILED description of ALL markings on both weapons, condition of the "fired" one, finish, grips, boxes, papers, accessories, history and serial numbers.
Impossible to answer without a detailed description of all features.
Unlikely
Impossible to render an evaluation guess without a detailed description
Yes
They're scary looking.
Without the proper skills and tools, doing so can become very dangerous. Even if you suceed, the gun would then probably become illegal - pistol grips on non-pistol firearms tend to be against the law.
most any large gun store will have them.
Grips, magazines, sights.
Best left to a trained gunmsith
Do an internet search for Colt SAA grips and be prepared for dozens if not hundreds of hits.
Check the markings on the slide, frame and grips.