Yes. A round dial cross slide will fit a square dial saddle. But there are two kinds of round dial cross slides: 9" and 13". The 13" are the same length as the cross slide used on the square dial, but they are not common. Each size uses a different rear chip shield. Round dial cross slides are shorter in height than square dial, so their chip shields are also shorter, and if you have multiple 10EE's you wont be able to interchange tooling as easily if you install a round dial cross slide on a square dial machine or vice versa (round dial and square dial machines have the same height from top of compound to lathe center line, even though square dial machines have ½" additional turning capacity).
