OK, my bad...
That's actually a Lyman 1B tang sight.
I can't tell what the front sight might be... how about a close up of it? Side and face?
Chances are a gun that fancy is going to also have a special order front sight.
Octagonal barrel was a standard offering at that time...
OK, I think I found your gun in a reprint 1905 catalog.
A little hard to tell, but the engraving pattern certainly has the Grade AB pattern.
Interestingly, though, the checkering pattern appears to be more like the Savage Leader (next step up).
Apparently you could part and parcel just about everything back then.
In 1905 your rifle would have cost:
Octagon barrel - $39.00
Fancy English Walnut - $5.00 (although that could be American black walnut, but would be the same price)
Pistol Grip - $2.50
No. 1B sight - $3.00
Front sight (est.) - $1.00
Estimated total, $50.50 in 1905, or roughly $1,200 in 2010 dollars.
I initially said up to $2,000 if you were to sell it today... I think you could, in the right auction, realize close to double that.