Just when you think you've seen it all. There's no doubt in my mind it's a Harder clock. I would say it's been altered. The question is when.
Here is a picture showing the previous numbered clock for comparison.
It looks like there are places where original holes were plugged. You can see shadows(circled) in this picture that correspond to the features on the other clock's plate.
I would examine those areas closely, and also the front plate, to see if they are indeed plugged holes. I would also compare how the wheels are made and marked to another Harder clock. Parts made later will likely be made different and have different or no markings. Compare the markings on the motion work wheels to the train wheels.
I noticed where the suspension is mounted took the addition of brass squares, which would be kind of a sloppy way for a manufacturer to design the clock. However, I think Eric nailed it with his observation.