Antonio,,, Interesting... Well I'm not a big follower of these rings. BUT. I'll give some common sense evidence..
1st, not sure if published but Don has said many years ago the skulls were cast,,then later soldered on the ring..

OK my understanding of 'Lost Wax', 'Investment Casting' etc. could be pressure induced or done centrifugal or simple pour..
I had a couple ideas about how the ring was made but no one seemed to interested at the time years ago when I mentioned the process.. BUT, lets stay with cast VS pressed.

So years ago when everyone was debating about this I had my friend bring authentic HR to NYCs diamond district. A famous area for more than 100 years where the Jewelers run the block and plenty of deals made! I showed an old timer [who has since passed on] who was alive during WW2 and has been in the jewelry business more than 50 years at the time. I showed him a 2nd pattern [late] HR.
He look at it for a minuet and asked,,,'How many were made? or is this it?' At the time I think I gave him a very brief history of the ring, and so many made each years etc. etc. His finding to me were:

Is this a perfect ring? My answer is no,it has defects etc. He picked up a ring from his shelf and said , 'is this a perfect ring?' My answer was,,yes. It was a beauty of a ring and flawless. He was really surprised when I told him how important the ring was that it continued to have the faults. He said its because they stayed with how that die was cut.

He said thats because the base of casting jewelry is wax. Hard waxes, soft waxes, etc. When a ring is carved from wax every imperfection will come out on the finished ring. Same with a ring made from a die.. The big difference is,,,
- with a die you have one. That one makes working dies and all the rings will be the same. All have the same faults, imperfections etc.

With a cast ring it too will come out with all the faults. But only a few. By the next batch that big die flaw on the Sieg rune would not be there. Same as with any other flaw.. With a die your stuck with it. The working die breaks or wears and another is made from the 'Mother die' and again you will have all the same faults..

Unless Firma Gahr made all their rings from one big day of casting the flaws, faults wouldn't be there period. We know he didn't make them all at one time..

With any cast ring then , now , whenever, It would be only the first run that would have the faults. AND even then it would be because of lazyness. I say that because when the wax model comes out a flaw could be fixed in a few seconds and then wax soldered to its tree for the burnout. That means every ring would have to be touched. Too much time,,SO they just wait to the next batch and then its repaired...

What I'm saying is and all this boils down to IF cast,,,we would only see the flaws/faults in the first batch. A flaw in a 1941 isn't going to be in the 42,43,44 rings.

Maybe Hapur will see this and weigh in,,,or we'll get some other opinions.. I have a theory but its only a theory,,we'll wait a bit and then I'll explain.., Thanks,G.