I wonder about that decorative slide. I wonder if there may have been an earlier model that used it and instead of retooling or getting rid of old castings they decided it would be cheaper to machine the base and install the slide.
No matter the reason for it, it's a cool design. Seeing things like that is why these old machines are so fascinating to me.
Seeing your machine reminds me of a machine I saw on Craig's List quite a while ago. For whatever reason someone painted "Sew Gem" on a Singer 101. It was definitely a 101. That's why it stuck with me. I still wonder why.
Rodney