All Zastava M57 are originaly without side safety. Serbian army recently sold 15.000 pcs of M57 army pistols to Austrian dealer. Pistols were then sold to US distributor, but had to be equiped with additional safety due to US regulations. The pistols were added side safety in austrian workshop, but the work was done by three serbian gunsmiths who came from Zastava Arms factory. Civilian M57 pistols have serial numbers that starts with letter "C". There were some minor changes in history of production of M57 pistols. In the beggining grip pannels were marked FNRJ (Federative National Republic Jugoslavia), after year 1962 the mark changed to SFRJ (Socialistic Federative Republic Jugoslavia). First produced pistols (not mor than 1000 pcs) had smaller ejection potr on the slide. The M57 pistols are stil in Zastava production program.