I’ve found sometimes pushing in with moderate force at the bottom near the channel seems to free up games. It’s also possible that it got badly wedged at the top during transit. You can try wiggling it at the top to see if it got hung up on the latch despite being unlocked.

Here’s what removing the lock will do. It should allow you to remove the translite,glass, speaker panel and all. Then you can separate the fused parts.

I don't think that matters on the older wooden head Sterns. There is still a wood channel on top when you remove the lock.

The glass is 'fused' to the channels on the sides an bottom of the head, sometimes to foam/ or other vibration dampening stuff.

Put both palms on the glass, apply enough inward pressure to keep a good grip on the glass and push up with as much force as you can. It's the only way I've gotten them off. I've had this on several machines and haven't broken the glass. Spread the hand pressure out, don't try to pry it out, that's what breaks them.

this happens to my T3 all the time, i have to gently punch all around the edges to free it up haha. must be the weather striping or something i never really looked into it

Glad you got it, what a pain in the ass. I hate when something simple is a million times more difficult than it should be.

I keep one of these with me when I pick up a pin project-
https://www.harborfreight.com/4-23-in-dual-suction-cup-lifter-125-lb-57501.html

It is great for playfield glass and for lifting out back glasses where the channel is broken.

Glad you got it out!

Looks like they already did their thing!
Make sure to neutralize that stuff!