Identify this sight

Can anybody identify this sight on my newly acquired 7" M41 barrel? It's not like the older ones. Also I swear that it works backwards from how its labeled as far as elevation.....is that even possible?

I'm guessing a old Series 100 Millet?

Ok, it may be me.Does that arrow mean clockwise or counterclockwise?

Counter for up.

yup, i was doing it backwards:oops:

Millet.

Thanks all. For some reason I just assumed that the arrow points which way to go from 12 o'clock. But as the arrow is at 6 counterclockwise makes sense.