Headstamps on base 20 x 138?

What is the meaning of the marking at the top of this 20 mm German WW2 base?

P397 Factory code in 1930s
38 1938
19e case lot
Eagle swastica M
?ReichsMarine inspection mark?
( For AA gun).


P397 = Meta Metallwerk GmbH.: Arnstadt.
Made in 1938.
Lot 19 Sublot e
Marine Abnahme, Should be;

Is it my eyes, or does the thing in the circle not look like a swastika, but more like a four pointed ‘star’?
I mean, I am gettin’ OLD…

I think I am at least as old as you as I also see a star