Question on 20x138Bmm case

Can you tell by the headstamp if this was a 2cm flak round, antitank, practice round?
And also would you leave it as is. Or remove the primer that bubba screwed up, and replace it with a piece of brass.
I know it’s a crying shame someone drilled a hole through it.

German 20x138mmB platzpatrone/blank as identified by the knurled case ring, sans hollow wood projectile. P181 =“HASAG”, Hugo Schneider A.G. FWIW, leave the drilled primer in place.

Nice waffenamt stamp! (Makes it all the more authentic!)

Thanks guys, I’ll leave it as is.