Need help with a lock salvaged from a historic psychiatric facility (~1870s) in the United States. I believe the lock to be Mallory & Wheeler brand, though it has no markings. It looks like the locking pin has been either removed or snapped off ( Pic 3 ) and lever 2 has two notch cuts. It looks like the lock either accepted two different keys, or the key was assymetrical, however when in the unlocked position the lever notch ( lever 2 ) would be engaged in the locking pin and appears that it would only allow the key that unlocked it to be capable of re-locking. I provided 3 possible renderings of the key.

Can anyone provide any insight with this lock?
Click image for larger version. 

Name:	1.jpg 
Views:	20 
Size:	669.3 KB 
ID:	17291Click image for larger version. 

Name:	2.jpg 
Views:	19 
Size:	635.6 KB 
ID:	17292Click image for larger version. 

Name:	3.jpg 
Views:	18 
Size:	636.5 KB 
ID:	17293
Click image for larger version. 

Name:	4.jpg 
Views:	18 
Size:	438.0 KB 
ID:	17294Click image for larger version. 

Name:	5.jpg 
Views:	17 
Size:	667.7 KB 
ID:	17295Click image for larger version. 

Name:	6.jpg 
Views:	14 
Size:	88.4 KB 
ID:	17296