Post 78 given the sn you provided
You will have to call Colt with the sn to find out.
@1964
Proofhouse.com has Colt sn data.
1974
100-1500 usd
You must call Colt with the serial number to find out.
1970
value depends on overall condition
1000 USD
Looks like a 1975 SP1. Here's a link to Colt Ser# http://www.biggerhammer.net/ar15/ar15serial.html Good luck 7.62
Impossible to answer without the serial number. Call Colt and they will tell you for free.
No way to answer without the serial number. You can call Colt and they will tell you if you provide the serial number.