Mid Century Modern Expandable Table

[tgarnold]

I'm curious about approximately how old this table is and any other information. I plan to sand and refinish the whole thing. The top has a couple of watermarks and is rough. It has a very basic style, but is all solid wood. I'm no expert on wood types, so any ideas about that would be great too. The bottom slides are marked Slides by Walter of Walabash.