Hi Batur,
All Me109's were designed to be pressurized as soon as the first G models arrived. All G models had a sealed cockpit tub from the firewall to the rear armour plate (which was the solid armour plate that sat flush with the back of the canopy glass on the G-3, G-5 etc.). The G was not sealed from the armour glass backwards.
The Erla Haube was not implimented until the late G6 Series, so a G-5 with an Erla Haube I think would not have existed.
Around 120 G-5/AS were ordered, but only 18 or so built, as when they went to the AS engine, some of the models lost their pressurization (not sure why).
The K series, which had the Erla Haube as the standard canopy had no change to the armour glass. The K was designed to be pressurized, and I have never seen an Erla Haube with any changes to the rear armour.
I am not sure how many K's were pressurized, if any...
Mike