You need to find a copy of The Book of Colt Firearms.
about 1894
I would say that your Colt Thunderer in .41 colt caliber was made in the year 1880-1881,with the serial number provided.
Proofhouse.com has Colt sn data.
1903
Model 1877 thunderer .41 with that serial number was made around 1890.
not aware of any DA colt 41's made in 1834 ?????
Caldwell Hart Colt died on 1894-01-21.
The Colt DA .41 1878 model was called The Thunderer.
Please include the model name or number to get the answer you are looking for.
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.
$3875