Hmm, is this the sceptre you find at Korianous's grave? That isn't labelled "restore mana", and no sceptres will behave like wands in this version of the game since I didn't know sceptres were wands. Interesting. Will reclassify and see what happens.
I did a bit of digging into the original UW1, and it looks like the sceptre in Korianous’s grave really was a functional magic item rather than just part of his grave equipment.
The original-game item data/strings include “Restore Mana” as a specific magical item effect, alongside Increase Mana, Mana Boost and Regain Mana. The magic-item location lists identify the item in Korianous’s grave specifically as an “Unblemished Sceptre of Restore Mana”.
I also found old UW1 player discussions, independent of the modern wiki, where players explicitly mention the magic sceptre on Level 1 as having a limited number of uses to restore mana, and identify its location as Korianous’s grave.
There also seems to be at least one other functional magic sceptre in the original game (the Sceptre of Ally on Level 5), so it looks as though sceptres could indeed function as charged magic items rather than being purely decorative.
So your idea of reclassifying them like wands sounds very promising. Happy to test it if you put it into a build! :)