this lock reminds me of a lock i had seen a book about ancient Egypt. but as far about "picking" per say. a curved hook should do it, well thats if u have seen these types of locks. if it was identified before the key should be made up in a short wile
i later foun out that this type of lock, well some thing like was made in roman times in england and also in otherpars of europe. it was not a popular style.
these are basicly a bolt with a removeable handle. but the ancient version was opened by a curved hook like a large fish hook. i do like this. this is a very good piece. u might want to add some bearing plate under the bolt , like a piece of thin brass. it will make the movement smoother. that or polish all the parts.
u might want to add some bearing plate under the bolt , like a piece of thin brass. it will make the movement smoother. that or polish all the parts. 
