Dave
That #4 is actually a #4C where C stands for corrugated. Those grooves were thought to reduce the force needed to operate the plane. Debatable but more collectible from what I gather. A #4 is one of the most popular sizes. That and a #5, aka jack plane.
Did you put the plane on a surface grinder at work to get the sole dead flat? Most people lap them on sandpaper stuck to a flat surface. Having a surface grinder would make that process effortless.
I do have a shelf full of planes and am working to restore them. However, they are largely repeats of the same plane. I think I have 6 #5s, 4 #3s, 4 #4s, etc.. I'm not really trying to collect planes, rather filling gaps where I have a need. The #40 scrub is a legit need and not for collection purposes.
I have a Craftsman plane in the batch that was actually made by Stanley. Wouldn't surprise me if your Monkey Wards was too. I think the dept. stores outsourced all their planes to the well known plane makers of the day.
Hey, if you want to do some spindle turning and need some black locust stock I'm your man. Let me know and I'll send you some sticks.
Eric