Those were interesting as it looks like they were using the old PR style keys. Hard to find a locksmith with that keystock to duplicate them.
The same style locks are used for desks and filing cabinets. Lowes has some in 2 lengths for about $5.00 ea. The package includes several configurations of the latch.
I had a 63 missing a locking bar. I used one of these and it worked with no modification. Now, instead of latching at the top and bottom, it locks into the same reciever, only in the center.
And in case you were wondering..........................NO, the round cam that you have from the lock you drilled out will not fit on these.
The square hole in the cam is different.