I've already looked with a borescope camera and there is no treasure on the inside.
Does that mean you've already got a hole somewhere in the safe section?
If so, you're halfway to the easiest way to get that lock open if you can reach the latch with a long screwdriver to push it open.
Otherwise, drill a hole in the back of the cabinet, centered on the latch edge of the door, at the height of the safe dial. Then with a suitably long flat-blade screwdriver, push or pry against the latch to slide it open (you'll be able to see it at the inside edge of the door). Then you can take the back off of the door to read the two disks in the very simple combination lock they used on those cabinets.
The dial operation is right to first number; left one turn just past first number to second number; right until dial stops, then turn slightly more to unlatch.
You'll be able to feel or hear the second number very easily, but probably not the first number. The third number doesn't matter because the dial will automatically stop there and then a little further movement in the same direction unlatches the lock.
And I need a key for the file cabinet lock
The lock is a 4-pin Chicago file cabinet lock using a Chicago CG17 blank (or Curtis CG17, ILCO 1041Y, Star 5CG4, Taylor 41Y)
If the top file drawer is unlocked, just pull off the retaining clip right behind the panel, remove the screw holding the linkage together, and take the lock to a locksmith, who can make you a key for $10/15 or so, depending what locksmith prices are in your area.
