Congratulations! You have an extraordinary shotgun. I have #3494 which is also a Diamond Quality and configured very similar to yours. Ken Georgi is the current keeper of the Daly records (I think he is the third). Hopefully he will chime in shortly. Using the A&D brevete and the serial number he was able date my gun to be circa 1885-1887. Assuming that Lindner made 100-125 guns a year (estimated production capacity of his work shop), your gun should be a year earlier..1884-1886. I also have #3070 which we dated to about 1880, quite early for a hammerless Daly. The actual Lindner production records are lost, so what Ken has to work with is an accumulaton of data provided over the years by Daly owners.
The markings on the barrels just ahead of the flats should be crossed pistols and a crown. That was the Lindner mark until 1892. The forearm lug should be about twice as wide as a normal lug. This is another unique Lindner characteristic.
Kindest regards,
Jon
