According to research by Waite and Ernst (The Trapdoor Springfield), your 1873 was manufactured in the last quarter (Oct/Dec) 1873. The number '25' on the stock is probably a rifle rack number so that it could quickly be placed back where it belonged in an arms room.
The number stamped on the square tang indicates the bit size.
Most likely the pattern number
If gold is real it will be stamped with a fineness number of 1-999 or .1-.999. It can also be stamped with a karat number of 10K, 14K, 18K, 22K or 24K.
Sterling silver is stamped 925 or .925 because it is 92.5% silver, and 7.5% alloy (usually copper).
it possible could mean size
The model number is stamped on the right side of the receiver on many Stevens products.
your 1911 was made by Colt in 1914. if your slide is marked 'springfield' it is the wrong slide for your Colt 1911. however, the wrong slide in use is not unusual.
It will be stamped into the side of the receiver.
The receiver is the frame of the gun. When a gun is marked with a serial number, it is stamped on the receiver. It will be a different part depending on the type of gun.
The serial number is stamped on the bottom of the receiver.
IF it has a serial number (not required in the US until 1968) it will be stamped on the receiver.
The serial number should be stamped on the bottom of the receiver next to the forearm.
On the front receiver ring,behind the rear sight.
It should be stamped on the side of the receiver.
Generally it is stamped on the side or top of the barrel near the receiver.
Serial number is stamped on the lower tang of the receiver. It is covered by the lever. Move the lever to see it.
Is it just stamped on one peice of the gun? I have a 5100 12g and each section (Stock, forestock and barrel) are stamped with a number (8WGK) to identify that they go together, kind of like a serial number.