I have a single molot 45 round ribbed poly RPK74 mag. It's very very black but sold as plum. I know true blacks of this type of mag are more rare in the US. At any rate, I read that using a super bright flashlight you can test Izmash 30s to see if they are plum (some light gets through) or true black (zero light gets through). The question is, does that test work on Molot 45s as well?