Noveske Lower Question

[Col_Crocs]

In the past there was a (1)CNC'd Noveske serif, safe-semi marked lower with a roll marked logo.
There is also the (2)fully roll marked safe-fire lower with serial numbers that begin with 0.
Lately, Ive been seeing (3)fully CNC'd markings, both safe-fire and safe-semi, with the E series serial numbers.
I think 1 is no longer in production but Im curious about 2 and 3. They both seem to be current and Im curious as to what the difference is between the two? Why have 2 types of markings and different serial number sets?

Did a quick search and found no conclusive result but if discussed before please post a link.

[spamsammich]

My best guess is the difference is due to the tooling available at the various machine shops that finish machine their lowers.

[SPQR]

E prefix are made by Kaiser, O prefix, i'm not sure.

[Col_Crocs]

Oh ya! Now it all makes sense. I thought the CNC'd safe-semi letters looked familiar.
I still prefer the roll marked ones though.
I know there are better things to talk about on the forum. Thanks for humoring me guys. I really appreciate it!