Hit: that looks like a Wilton Tradesman. Wilton did make a few of them in China, but I'm pretty sure they make the new bullets and tradesman vises in the USA now. with the chip out of the jaw tower and the jaw off I'm wondering if the threads might be stripped. the jaws on those vises are not made from very high quality material either, but it is a Wilton so if the price is right it probably needs to be bought.
pull out the dynamic jaw to check out the insides since it took that blow to the top of the vise and while you have it apart you can check out the date stamp on the keyway that is sometimes hidden in grease. I think the made in China Tradesmans have an open bottom in the swivel base's design, but not 100% positive on that.
SHIFT: i think you needed to post up the picture with your shelving unit full of vises?
BAGGED: i've got this STOUT shelving unit that I've had 2500-3000 pounds of gym weight plates on each shelf, but I've got a little 4 foot wide shelving unit with 3/4 inch pressboard on it's shelves that holds a fair amount of vises too. i know you own the 2x10's, but a metal framed shelving unit can be found fairly cheap and use the wood for another project.