Joe, Serial numbers started at 1000 so your gun is very early. A Jan 2, 1925 Wholesale Price List is the earliest dated material I have with the Model 25 so the model might have been in production in late 1924.
I have a copy of a letter on serial number 1468K but that raises more questions than it answers, the K indicates it's a house brand and I was under the impression that they were included in the same serial number sequence as the Savage labeled guns, in fact this is stated in the letter. This letter brings that into question because it states the guns was "shipped June 8, 1926" which seem way to late for that low a serial number if it were in the same sequence - the letter does not include the date the gun went to the warehouse, just the ship date.... was it entered wrong? ...or was the order held up for a long period? This is the only letter I have that does not included the date the gun went to the warehouse.
The Model 25 was an improvement of the Model 1914 which was basically a tube fed version of the Model 1903, that's why your Model 25 has Dec 25, 1906 as one of the patent dates, that's the date of the patent for the 1903 which covers some of the design. That patent would have expired by Dec 1921 from the information I have, but there is no law I know of saying you can't still list it. There were no new patents for the Model 25 since it was just an improved 1914.
These house brands all have the serial numbers followed by a 'K' and other than the Premiers have numbers under 6600K, the Premiers have the later design forearm with two screws on the right side only and all I have seen have serial number between 10,000K and 17,000K which means the certainly were in the Model 25 serial number sequence, there could not be that many Premiers made.