What's the deal with SilverWave wavy springs?

[tritto]

Hey guys. I have a question/theory.
I've had three 30m Silverwaves and two have come without wavy springs under the crystal.
When I took the crystal off the most recent SilverWave and found no wavy spring I had a look at the bezel and it didn't look like there had ever been any rubbing from a spring on the top outer edge. The one that I have that does have a spring has a slight indentation.
The bezel on the new watch doesn't seem to ride up without the spring and the gear engages properly.
I have a NOS 341W02AN crystal (also without wavy spring). I compared it to the crystal that came off and the cut out on the inside edge seems fractionally deeper on the 341W02 than the crystal that came off.
I've read that the 50m SilverWave originally came with the 343WH2 and no spring.
Is it possible that the 343WH2 has a smaller cut out and that my new 30m SilverWave has that crystal fitted - hence no need for a spring?
Did all 30ms come with a 341w02 and a spring?

Rod or anyone else?

[Rod]

The old MA34W is as you've correctly surmised, is different from the later 341W02AN. Only the later crystal needs the wavy spring as the clearance between the crystal and the rotating ring is sufficient to allow the ring to come away from the stem gear, which if it slips (the ring is plastic and the stem gear steel) can then damage the ring gear.

[tritto]

Nov 27, 2019 19:55:48 GMT -8 Rod said:

The old MA34W is as you've correctly surmised, is different from the later 341W02AN. Only the later crystal needs the wavy spring as the clearance between the crystal and the rotating ring is sufficient to allow the ring to come away from the stem gear, which if it slips (the ring is plastic and the stem gear steel) can then damage the ring gear.

Thank you. That gives me some confidence that the newest watch is as it should be. Now I can go back to one of the others and check that crystal to see if it has the same cutout and it's not a later 341W02AN that's lacking a wavy spring.