Well that didn't come out very well but if you scroll on the first pic you can see the breech and below it. Will take my picture problems back to the drawing board.

Resized the photo for you.

I'm not the expert here on Ballards but she looks pretty solid under the barrel.
The guys that know them will be along shortly.

Nice looking rifle by the way!!

Yes, there are several what look like set screw marks but only 6 grooves. Is that a clue?

I would guess that it is not a Peterson or Schoyen and that it was fairly recently built up--but I don't know it all.

Two line address does not indicate when the gun was made. What's on the address does indicate this. A two line address often indicates it's a forged action, which yours is. But if the address is "JM Marlin" it indicates 1881 or before. If it's "Marlin Firearms Co." it's 1881 or later.
Your barrel appears to have a liner in it from the noticeable ring I see at the chamber end of the barrel, so most likely not a Schcoyen bore. But 6 grooves wont be a Schoyen anyway. 
It's a very lovely old Ballard though, and I especially like that lever and buttplaate.

I can tell you which it might be, and which it likely isn't. But impossible to tell exactly what model it is. If the breech block halves match the receiver number, then it's likely it started life as a Union Hill. And a #8 had set triggers, so if the blocks serial number to the action it's likely the #8. The stepped side receiver eliminates some other pistol gripped receiver models like the #6, or others that usually have flat sided receivers.
The very high serial number, and Marlin Firearms Co. stamped receiver indicate it's in the very last Marlin Ballard rifles produced, and almost certain it's from 1890 era.
Yes, it's likely a pieced together gun, as most dedicated schuetzen rifles often were. The question really is how pieced together it is? The stocks, buttplate, lever, are all non Marlin, so added later. The barrel should have a matching serial number under the forearm, and if none, then that too was changed. As I mentioned, if you drop the lever screw and remove the breech blocks, you can examine the rear tail of the breech block halves for a serial number. Each half has the same number, and if it matches the receiver, then they started with a complete Marlin Ballard action to build the rest of your gun.

Fantastic. Will drop the block and check the no's and see how they match. I am delighted to learn about this gun. 
Just for show and tell, below are some of the tools that came with it. 
John