Model 1892 Krag, serial #876, is mentioned in a letter Mordecai submitted on changes to the model.  Reference can be found on page 53 in "The Krag Rifle Story" by Mallory and Olson (1979 edition).

The rifle later was altered to 1896 standard.  Sometime after 1944 it was heavily sporterized - it has a Remington 1944 dated '03A3 barrel.

Thanks to Ned and Tom the gun is in my living room.  I was hoping to be able to study the receiver to see if any of the "breech changes" can be found.  Again, the gun was altered to 1896 standard so the receiver is the only part assured to belong.  Thus far, not having taken #230 apart for a compare (I'll do that in time), all I can say is the feed lip modification of the later 1892s doesn't exist on this one.  In other words it retains the earlier feed lip.

Again, thanks Ned and Tom.  While there isn't much left of it the receiver itself will make for an interesting study.