The one I had had the swing out support. Is it missing on that one?
They're nice cabinets. You can't buy the wood to make your own for $35, let alone the hinges and other hardware.
Find a new piece of furniture made of high quality solid walnut and walnut veneer and see how much that one costs.
Antique furniture or even good quality vintage is almost always a bargain compared to new.
If you like it, get it.
I think this ad has the arm in the back.
http://www.ebay.com/itm/Vintage-Sing...item33a35bc9b9
Rodney