I would not advise that. But only because the bearing may not press over the stem nicely. Also never use Anti-Seize.
- Oil or grease are better choices during installation...
The stem is solid and the slice won't hurt it. If it were mine, I'd take the smallest round file and lightly deburr the edges. The goal being removal of sharp edges where cracks can start. Its covered by the bearing so it should be fine.
That said: if your steam breaks, don't blame me!
FWIW: i would not hesitate to use it. Just deburr first.
+1 on what he said, that little nick isn't too bad, just remove any burs with some Emory cloth or something similar as to not take too much material away and you should be fine