1994 cutlass supreme Brake Booster replacement

[AjMillerKing]

My father owns a 94 cutlass supreme convertible and its brake booster has failed. Everywhere i look for steps to replace the booster mentions 4 bolts holding the booster from inside the firewall, however, when I go to look, no bolts are to be found. When I look at the new booster, it seems to lock into place using grooves and some kind of locking bar.

Nothing I do really does anything to get this booster to move and I am stumped on how to progress. The coter pin is out and the pedal disconnected. The master cylinder and abs contraption is off and out of the way. Theoretically, it should pop right out, yet it holds firm.

Any help would be greatly appreciated! Thank you in advance.