The goats foot cocking lever should just be applied for loading of course. The form appears to be one for conventional firing (carried no mounted on something), but the extended slot for the bolt is a new one on me, as is the sectioned steel bar for a string.
As to the age, these can be deceptively modern despite the archaic form. Take out one of the flat countersunk screws on the bolt holder and look at the thread. That'll give a good idea of age.
Sort of reminds me of the second one I posted in this thread: