Case Savers from inside the case????

[Bug53]

As evidenced by my string of posts lately I have been hot and heavy on getting my bug on the road.
One thing leads to another.
Took compression readings (all 145-150) before pulling the engine to check the clutch, fix a main seal leak, etc.
While my tin was off getting painted I decided to retorque my cylinder heads.
All is well, I see a few case savers on the left side, then I get to No.3 and while torqueing and watching to see if the studs turn I notice the upper left stud is in a recess and obviously threaded into an insert or case saver from the inside.
It hasn't leaked a drop , has no threads in the hole and has been like that for around 10K miles.
Am I missing a new technique? WTH?
Your thoughts appreciated.
Thx.

[gt1953]

Number three cylinder top front stud is deep sunk like it is supposed to be,
_________________
Volkswagen: We tune what we drive.
Numbers Matching VW's are getting harder to find. Source out the most Stock vehicle and keep that way. You will be glad you did.

72 type 1
72 Squareback
({59 Euro bug, 62, 63, 67, 68, 69, 73 type ones 68 & 69 type two, 68 Ghia all sold})