For guns around 1905, you may have happened on a "light weight game gun" made with thinner walled barrels on purpose. Barrels may have been about thirty inches long originally and perhaps been under .025 at the thinnest points of the walls. The tendency is to not go that thin now and make the barrels perhaps twenty-eight inches long to try to achieve the desired balance.
For example, a Stephen Grant from that period would typically be as described and might weigh a few ounces shy of seven pounds. The pair at Holt's are a good example from the April 17 catalogue.
You will need to take a look at the how the gun feels as well as compare to original to check out the points raised. It may be a great buy that will answer your needs or you may bemoan what happened to an otherwise lively gun.
