Mid Century Modern Expandable Table

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.
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It's relatively modern production furniture with unremarkable joinery. most likely with dowel or biscuit joints where the legs joint to skirt due to the metal brackets on the back of the leg posts. Refinish and enjoy, don't expect it to have much re-sale value. Good luck.