Are the glass vials banana shaped (curved glass)? Does it have a vial for the horizontal plain, plumb (vertical plain), and for a 45 degree angle?
I'd say if it has all three vials, it's likely a carpenters level. It's relatively long at 63" so IF the 45 degree vial is missing look to see if there are plomb vials on either end. I would not be shocked to see a carpenter's level configured (in that length) with plomb vials on either end and absent the 45.
Most modern iron-workers levels I've seen are magnetized somewhere, somehow. You may want to check for magnetism.
My gut reaction, however, was a line level given it appears it could be hung or suspended. Having said that, I find a line level practically useless. I can't imagine a modern day line level being made of mahogany and with such detail. We have transits now, and cheap ones.
I think whatever it turns out to be the two swiveling hooks/eyelets, whether it has a 45 degree vial, the placement of the plomb vials, AND the unique angle on the wood stock will have been clues.