Values are based on the actual condition, finish, box, papers, accessories, whether any modifications have been done to it since it left the factory. It is basically impossible to put a value on any firearm with just the caliber and model provided. You could be in the 50-400 USD or more range. A hands on evaluation is needed.
From the records I have, the Colt frontier scout .22 Q model was produced in 1967. (210500F-223199F) about 1967
1967
50-250 usd
@1967
Made in 1967.
Don't know value, but was produced in 1967.
Your colt frontier scout was made by colt in 1959.
Produced around 1967.
50-275
Your colt frontier scout 22lr was produced in 1960.
Your colt frontier scout was made in 1968.
Could not find a Colt frontier scout with serial number 56599P, but a Colt frontier scout with serial number 56599F was made in 1959.