The knife shown here in the original post may have indeed been end of days knife, or it may have been just a case of an Uncle Henry blade mixed in with some 8OT blades.
Notice that the tang stamp on the clip blade says SCHRADE+ on the top line of the tang stamp. This signifies that the knife was made with stainless steel blades. However if you look at the other two blades they are obviously discolored and have developed considerable patina. This tells me those are carbon steel blades. In general the blades of a knife are all made with the same type of steel. What you have is a 8OT with an 885UH blade.
How did that blade ended up in an Old Timer? It may have been an 885UH blade dropped on the floor next to a machine where they were assembling 8OTs. Someone may have picked it up without looking assuming it belonged in an 8OT and tossed it in the blades being assembled in the 8OT's. Or it could have been they run a batch of 885's and one blade got hung up somewhere in the machinery and when the 8OT blades were dumped in the machinery and not the 885 blade loose, and it was installed in an Old Timer.
The wrong blade in that knife doesn't necessarily make invaluable, to me one would make that knife valuable is the fact that it belonged to someone I loved.