Nice old machine. The castors are handy to move it but you want to get them off and level it properly once you have decided where it will live. If you leave it like that you risk twisting the bed, especially if your floor is not flat.
Lovely little machines, you will have lots of fun ! Much better than a Myford, and I speak as the proud owner of a 1940's ML 4, a nice old machine but only really good for very small stuff as it's very flexible. The small Boxfords have those nice wide bed rails, making for a much more rigid machine.