No keys are necessary to remove the top of an NCR 1090, very often made in 1947 and meeting the original description. But you must be able to use a straight slot screwdriver with some finesse.
The assumption here is you do not have the keys. Just above the drawer there is a metal bar installed with two screws facing the front, one facing the top. Remove all 3. Now with a little pressure from the screwdriver spread the gap and slide the drawer out past the lock. Once open past the lock, the draw will slide almost all the way out. The second from right rear compartment has a little lever in the back that lifts a pin. Once lifted, the drawer comes out.
The same type of lock exists on the left side. To get past it, take the 8 visible screws holding the front panel out. This gives some play to the lock area and the gap can be carefully pried open releasing the lock. The 9th and last screw for taking off the front panel is now somewhat accessible in the paper compartment, near the door you just opened, facing down. Ease of doing so will depend on what position the paper roller is in.
The top lock does not need to be unlocked to remove the rest of the cover. There is one screw at the bottom on both sides, and four in the back. Remove them and lift the cover straight up.
You just did a hack … 1947 style.
Tom Burke, California
tomburke1@sbcglobal.net
re: NCR 1090 w/o keys. 9/1/19 revised 9/4