Call Colt.
You could get a historical letter from Colt. Cost is about 100 USD or so.
Don't know the value,but a Colt police positive .32 with that serial # was produced in 1908. Or, 1909
Proofhouse.com has Colt sn data.
Need to know what type of Colt to answer.
mfg. about 1910 I cannot tell you the value
Don't know value,but the Colt new police .32 serial # 18685 was produced around 1904
Your Colt DA .41 with serial number 207840 is 103 years old.
probably made before 1907. value depends on condition
Based on the serial number, your Colt DA .41 would be 103 years old. It was made in 1903.
Check the model as written on top of barrel.
Virtually impossible to answer with just a patent date.
probably due to patent changes....................