Well because someone peaked my interest in finding any attribute and req on Bone Dragon Staffs with no inscription shot, if you have one, or have a screen shot of one, post it here. I will like to refrain from using the acronym OS because IMO, they shouldn't be classified of that. I know EotN came out on August 31st, 2007 still within a small window of the considered OS era. It's still a place of inscribable weapons and such.
-Deals
No Inscribable Bone Dragon Staffs
Deals13
Enchanted Krystal
Plenty of them out there, so GL finding them. I had one a few years ago, but long since sold it. 
Deals13
I'm in no way interested in buying just trying to see how many exist lol
MaxBorken
Talk to Zephyr. He's been chasing those for a long time.
Max
Max
Pleikki
I cant say for sure but within last year ive seem somewhere between 10-20. So prolly alot more rxcist
Rushin Roulette
As far as I know, these staves can still drop from the chest with a very low (even lower than the regular versions of course) chance.
Therefore, given enough time the supply will only increase as long as the dungeon is still farmed and the bug is not fixed. It would be possible to guess at how many existed if we had data on how many runs were done and what the droprate for this bugged staff is (not really possible though as this data was never available or never compiled from the servers).
They can not be titled OS, because they have no fixed inherent which would be the inscription slot. The only way to title them would be bugged items as they are regular inscribable staves.... just with the inscription slot missing. You sometimes get these in NF and the rest of EoTN as well.
The closest thing for approximation would be what Ikki wrote. 10-20 known to him and a lot more not recorded because they went straight to the merch or are wiling away on some forgotten hero/inactive account.
Therefore, given enough time the supply will only increase as long as the dungeon is still farmed and the bug is not fixed. It would be possible to guess at how many existed if we had data on how many runs were done and what the droprate for this bugged staff is (not really possible though as this data was never available or never compiled from the servers).
They can not be titled OS, because they have no fixed inherent which would be the inscription slot. The only way to title them would be bugged items as they are regular inscribable staves.... just with the inscription slot missing. You sometimes get these in NF and the rest of EoTN as well.
The closest thing for approximation would be what Ikki wrote. 10-20 known to him and a lot more not recorded because they went straight to the merch or are wiling away on some forgotten hero/inactive account.
The Mountain
These do not drop any more. They did drop for quite a while, though, until they fixed the bug with vs undead mods on inscribable weapons. As a reminder, inscribable weps that had the vs undead mod sometimes did not contain an inscription slot. There were quite a few posted back then (and some even left on the floor of the dungeon) when people saw what they had and raged about the worthlessness.
Zephyr of Light
Personally got around seven and got those customized by friends (because why not).
(Just want too note, I also own the only non-inscriptable Obsidian Edge in the game, only because no other has ever seen before
)
Im pretty sure they still can drop to this day as its purely a mathmatical flaw in the loot tables, presumeably just a calculative chance of it (anything) being able too drop without an inscription slot, just like non inscriptables can do more frequently seen.
The odds of this too happen with inscriptables is maybe 1 every 100-200 drops (1 / 0,50% ) to my estimate.
(Just want too note, I also own the only non-inscriptable Obsidian Edge in the game, only because no other has ever seen before
)Im pretty sure they still can drop to this day as its purely a mathmatical flaw in the loot tables, presumeably just a calculative chance of it (anything) being able too drop without an inscription slot, just like non inscriptables can do more frequently seen.
The odds of this too happen with inscriptables is maybe 1 every 100-200 drops (1 / 0,50% ) to my estimate.