Looks like a nice Alcoso police bayo! Can you tell if there is a letter next to the police property stamp? Sometimes there is, sometimes not. I would add that the blade looks like it could use a good wipe down with a rag and gun oil. To me, it looks like old oil has dried on the blade giving you a"rainbow" type effect.
this is a Seitengewehr 84/98, a Bayonet 98 k never existed.
This is a typical police property stamp.