I just acquired a Stevens Favorite with the serial number 777 and had a few questions for the Stevens collectors.
The rifle has a 24" barrel with octagon in the rear and tapered round, starting just in front of the forend. It is marked 25 Stevens and chambered for the 25 RF cartridge. The barrel is also marked with the J. Stevens Arms and Tool Company and Chicopee Falls address. The action is marked "Trademark, Favorite, US Patent Off & FGN" on the top flat. The extractor is located at 6 O'clock and is the narrow type.The number 777 is on the bottom tang and the top tang has no marking but is tapped for a tang sight, with a screw spacing of 1.488".
I'll attach a selection of pictures and can attach additional pictures, if needed.
I wonder how common custom numbers are seen on Stevens rifles? Does anyone know what tang sight, with the 1.488" spacing, may have been used?
Thanks in advance for your help.
Otto

Interesting favorite. The earliest favorites had serial numbers with the number stamped on the lower tang and matching number on the barrel just ahead of the forearm on the bottom. After selling a huge amount of favorites Stevens went with assembly numbers, typically with a letter and three digit number code. With the trade mark Stevens stamping on the top flat of the frame, my guess is that it is one of the last 1894 model favorites made before switching over to the 1915 model. 
Is the Stevens A&T stamping on the top flat of the barrel or on the right side flat, sometimes thought of as upside down?

The hole spacing on the tang sight is always referred to as 1 1/2 inches. There were a couple of sight options on these using standard Stevens tang sights and front sight combinations. Plus they would sell you any sight that would fit and since they were all 1 1/2"  space on the sight pretty much anything goes. Lyman sights were also available from Stevens.

Westerner
Just kidding about the numbers. No provenance. I don't see any additional numbers but haven't taken the action apart yet. I wonder if it might be an assembly number. 
If the 777 is a serial number wouldn't this make the action earlier, than the extractor suggests?
44
I think that the holes are on nominal 1.5" centers. Do you know which Lyman or Stevens tang sights may have been used on the Favorite?
Otto

444 cannot be a serial number.  Favorites were in the high five digits while they still had the 7:00 extractor.  If memory serves, they were into four digits while it was still the "side plate" design.

Not even that late.  I've only recently started paying the same attention to the Favorites as I have the Model 44.  It appears that the transition from the serial number to a lot number happened around 1896, close the the same time as they changed the breechblock cutaway from the early sharp angle to the radiused shape yours has.  The 6:00 extractor seems to have appeared around 1900.  When the width of the extractor changed is anybody's guess, AFAIK.   

They made a helluvalot of '94 model Favorites, possibly approaching a million by WW1.  No wonder that they're so common today.   

Barring horrendous abuse, the only things that you commonly find in need of help are the bore, which suffered through the era of corrosive priming, and the linkage.  The link was made of mild steel, and the holes open up from the stress of firing, especially firing with high speed smokeless ammo.  Bores can be relined, and the linkage can be restored by installing oversize (4 mm) pins.

Thanks to all the members, who took the time to answer my questions.
I have a bit of repair work on the broken buttstock toe and buttplate but overall the lucky Favorite is in fine shape, with an excellent bore and tight action.
The bore slugs at .251" and 27 caliber nail gun cartridges are a perfect fit. I plan to shoot this Favorite breech seated, once the proper lead bullets arrive.
Otto

uscra 112,
They do warn about the danger of using the high powered nail gun cartridges in nail guns designed for the weaker cartridges.
The 25 Stevens RF smokeless load is listed as using a 65 grain bullet and had a velocity that is said to have been 1180 fps.
My plan was to use a Stevens 44 1/2 rifle to test a 50 grain bullet and check the velocity, with the low powered 27 caliber nail gun cartridge. 
Do you think that a muzzle velocity below 1100  fps is an adequate indicator of safe operating pressure for the Favorite? 
If not, I suppose I could turn some 25 RF cartridges, powered by 22 RF cartridges, without their bullets.
Otto