Searching for complete mortise lockset 13/16 width , satin nickel

I am afraid this isn't enough information to go off of. Can you send us pictures of the existing hardware? I'll do my best to find replacement hardware for you from there. 

We don't have an exact match for this handle set but we do carry some possible replacements. Take a look at our 40-152 or 40-130, or maybe even the keyed 40-177 to start. Compare their dimensions with your old handle set and see if you think any of these options might work as a replacement. Let me know what you think.