That looks more like a Bigsby than a Vibrola to me. Vibrolas look like these:
http://shop.ebay.com/i.html?_nkw=maestro+vibrola
That looks like a Bigsby B5 that was maybe rebranded for Maestro (or perhaps a Bigsby copy). Here are some B5s:
http://shop.ebay.com/i.html?_nkw=bigsby+b5