Yes, very beautiful, interesting that it has a lugged hammer when it is a .22LR. Does it have a 7 o’clock extractor?

What is the serial number?  There's a very narrow range that had the two-part "bolt" pivots combined with the 7:00 extractor.

That number is way, way out of sequence for the features we see.  At that s/n range, it would have screw pivots diameter .258", for example.   Side extractor and bolt pivots together from the factory happen around 12,000 to 16,000.  Unless the gunsmith who built it converted from the screw pivots to the bolts, the frame is from that vintage.  If it is an earlier frame that was converted, it would have to have been done before the engraving work.

That barrel might have been taken from a 44 1/2, and reworked to fit the 44 frame.  The 44 tenon is smaller than the 44 1/2, so it would be an easy proposition. The 44 tenon is a bit longer but the setback necessary would only be about 1/16 inch.  

Edit:  Nope, I take that back, the threads wouldn't clean up.  The setback would have to be more like an inch.

The tension screw in the breechblock leg disappears with the introduction of the 6:00 extractor.  The slot for the extractor occupies that space.

Yes, it could be a very early barrel, probably relined.   

So far I have seen the lugged hammer only in rifles built for the largest centerfire cartridges; .32-40 and .38-55.  Even the .32 Ideal and .32-35 rifles I've logged do not have it. (Rebel reports that his rare .44-40 has it.)

Thanks for all the info, this site is a great resource!
The barrel is 30" long, muzzle to breech face. Doesn't appear to be set back- The 2-screw fore end is normal length, and the barrel S/N is in the right spot just in front of the wood.
It doesn't appear to have been re-lined-neither the muzzle or breech show any sign of that.
Here are some more pictures of hammer and RF breech block, muzzle, markings and engraving.

muzzle

A couple more questions-
When I got it the rifle was topped with a 20X unertl, but the barrel shows various scope attachments over the years. What kind of mount used the eyebrow notch visible in my marking photo? Was it a claw mount of some kind? There are 2 in front and 2 in back about in the same locations as the blocks.
As for hammer lug am I correct about it being there? I take the wedge shaped projection under the striking surface to be it, but honestly I've never seen one maybe I am wrong. I too wondered why it would be on a 22RF.

Those "eyebrows" are the cuts made to mount Harry Pope's own style of scope mounts.  Pope cut them, of course,, and Stevens may have while Pope was working for them, but I don't think anyone else did, at least back then.  In short, at some point - and I'm guessing early on - Ol' Harry may have had a finger if not a hand in the evolution of your rifle.

Bill Lawrence