A serial number is needed to answer the question.
Congratulations
The S&W Model 57 chambered in .41 Magnum with a 6" barrel will range from about $400 to $2000 depending on condition and age.
You will have to call Colt with the serial number to find out.
Your Colt DA .41 with serial number 207840 is 103 years old.
Proofhouse.com has Colt sn data.
about 1894
Proofhouse.com has Colt sn data.
made about 1883
1891
1881
1901
Based on the serial number, your Colt DA .41 would be 103 years old. It was made in 1903.