Thread size for mounting TDK-Lambda LS150-24

Just bought 24V dc power supply, works great. But I need to mount it and cannot find “standoffs” or mounting screws with the fine thread needed for this component. The mounting instructions mention M3 and M3.5 threaded screws but these are to large for the female threads on the bottom and sides of the LS150-24.
I have some M3 fasteners with male threads but they are too large to fit.
Are these mounting holes meant for 4-40 threads?
Any and all suggestions greatly appreciated.

The mechanical drawing for the LS150 indicates that the mounting holes are threaded for M3 screws. A 4/40 screw would be a hair smaller than an M3, so if you’re absolutely sure that it’s M3 screws that you’re holding I’d give 4/40’s a try.