I find the hallmarks a bit odd. The 84 mark is lacking the kokoshnik mark
on the blade. The maker's mark and assayers mark seem to be there, though, but I have not seen it done in this way before.
The left facing kokoshnik mark is on the very tip of the scabbard, but does not include the 84 mark. There are no other hallmarks.
Hope this makes sense! It is a sweet little item - possibly a toothpick?
Here are pictures of the dagger:


