Like anything, you get what you pay for.
Lower price = lower quality.
Good pistol
Here is a good page on how to field strip and clean the colt 1911 pistol. http://www.bobtuley.com/45/magazine1.htm
100-460 or so
Proofhouse.com has Colt sn data, 100-1000 USD
Ok
All together they are a good quality 1911 pistol, although I have heard some claims that they are too tightly fitted and may jam after a certain number of rounds are fired or when you get dirt in the action which means that their quality could make them a little fussy but if your not in a combat situation and just using it for self defense or as a target gun then there just as good as any other 1911, although i think you can get the same quality in a cheaper gun and that's why I won't buy one I'd go for a cheaper 1911 (in the 650-900) range such as the colt series 70 $900 and the new Remington 1911 r1 $650 or the Springfield mil spec 700$ any of these are just as good as a kimber and at a cheaper price
Need a good description in order to even begin to attempt to put a value on it.
the M21 Colt 1911 is quite good even though its spring
Best left to a good gunsmith. Depending on exactly what you have, you could devalue it with improper cleaning.
50-600 usd
value depends on overall condition of pistol. good condition can average $800 -$1200
about 1912