You have written your question in a way that guarantees it can not be answered. In order to answer your question you left out the most important piece of information. You did not provide the serial number. Serial number data has been published in many books. The Blue Book of Gun Values is one. Alternatively, you can call Colt with he serial number and they will tell you.
No way to answer without the entire serial number. You can call Colt and they will tell you.
To determine the age of a Colt AR-15 A2 HBAR Sporter with the serial number SP221219, you would typically need to consult Colt's production records or a firearms expert. However, Colt generally produced the Sporter model in the late 1980s to early 1990s. Based on the serial number, it's likely that this particular rifle was manufactured in the late 1980s.
Yes
600-1200
100-1500 US dollars.
The Colt AR-15 HBAR Match with serial number 015317 was manufactured in 1995. Colt's production of the HBAR Match models began in the early 1990s, and this specific serial number aligns with that timeframe.
Model 6601
100-1000 usd
I just purchased one from a dealer in like new condition for $1,000. I believe that to be the low end of the value of this gun. Most in this condition will be higher.
Fiind a copy of "The Black Rifle", both volumes. You can research it then.
500-800 depending on what "very good" turns out to be.
Very poor description to base a value on. Broad range 300-800 USD.