As an avid collector of 73s for over 30 years I can tell you for sure that it won't be much.
There appears to be virtually no finish left on the metal with the exception of the lever, hard to tell for sure and some pitting as well.
I am assuming what appears to be staining on the frame is from the can of Kroil oil?
The big gouge in the barrel don't help none!
The additions to the wood (unless done by someone famous back in the 1800s and documented) may add value to a novice collector, as eye appeal only, but it does little, if not detract from a collectors stand point.
Depending on various things like barrel length (standard was 24" round), standard or adjustable trigger (appears to be standard) deluxe sights (appears to be standard on the rear and possibly a replacement), with standard walnut wood that has been carved.
While this is an interesting gun, in todays market I would place a value of $600.00 to $1000.00 tops.
I wouldn't pay the top price because of the condition of the metal and all the changes made to it.
The only thing it has going for it is the fact that 38-40 was a little rarer than the 44-40 or the 32-20.
Looks like a nice shooter and for that it is well suited but as a collector it would do for someone just starting until they could find one in better condition.
Just my opinion!
Others may say differently.
LONGTOM