Tom, your safe looks to be 1850-60’s and possibly from Boston. That type of lock was fairly popular then and there were several different styles and makers. Turning the handle CC would raise the levers or sliders up allowing the key to be inserted into the slot. Then the handle would turn further to the right pulling back the bolt. Typically the locks are right up against the outer door plate, facilitating drilling into them. I won’t say picking is impossible but getting it open without drilling is not likely to happen. Unfortunately, unless you know exactly where to put the hole(s), it is easy to make a mess of the lock. Also, if you are not properly equipped with a scope, this job may prove overly difficult. Adding to the difficulty, is that the locks are typically buried underneath the insulation, making removal of the lock a real pain once the safe is open. If at all possible, identifying the safe and lock are the first steps. Strip the paint off to see if the original paint has the maker on it. I know of one possible patented lock that may be what you have. I will post it later. Doug