There were several different designs for the "typewriter desk" and I can point out that every one I am aware of was designed for a desktop, "standard", office typewriter. It seems that, originally, only these big tws needed such an arrangement to get them out of the way easily by folding it or sliding it into the desk. Smaller ones can just be whisked away. In later years there were smaller versions marketed to students but they didn't have flip up top panels, just an area of lower surface or maybe a drawer for the tw. My own flip-top desk hides a Royal 10 and even a wide-carriage tw would work in it because the carriage is above the adjacent edges when it is deployed, though it has to be centered when put away.
In short, i would be very confident that a Sterling would fit. The trick is to anchor it so it doesn't slide when folded away. The desktops had threaded holes for bolts to anchor them through the surface. The bolts on my Royal turned out to be metric 6x1(!) instead of the expected 1/4x20. You'll have to rig something for your Sterling, plus, of course, it will no longer be quite so "portable".