The sporting section of most large book stores carry pricing guides (similar to the Kelly Blue Book used to determine the value of used auto's) that attempt to give values to most used firearms. They generally do a good job. Many gun shops use them when buying used guns.
Colt has not offered a AR15 in 308
If you call Colt they will tell you when it was made.
10-10000 USD depending on specifics
Proofhouse.com has Colt sn data.
Colt never made this weapon.
it is worth about £278/$313.
Colt was not in business in 1800. Samuel Colt was not born until 1814.
Colt has never made a 45/410 pistol
the 45. colt combat commander i worth from 1100.00 to 9000.00 depending on the gun research carefully.
50-300 usd
A Colt 22 target pistol can be worth anywhere from 100 to 500 dollars. This all depends on what shape the gun is in.
value depends totally on overall condition. you can own a junk colt worth $200 in parts. or, a good condition colt worth $1000 or more.