The photograph on the left shows the markings that are found on the right side of this Colt Mk IV pistol. Looking through the ejection port, the barrel has been stamped "CAL.380". This mark indicates that the pistol has been chambered for the .380 Automatic Colt Pistol cartridge. Directly underneath the ejection port, the slide has been stamped as follows, "GOVERNMENT MODEL". The right side of the receiver has a two line inscription stamped on it as follows, "COLT'S PT. FA. MFG. CO." and then underneath that is "HARTFORD, CT. USA.". The first line of this inscription indicates that the pistol was manufactured by Colt Patent Firearms Manufacturing Company and that they are located in Hartford, Connecticut in the United States of America.
The photograph on the right is of the slide inscription that is found on the left side of the slide. The top line is as follows, "COLT MK IV/ SERIES' 80". This top line indicates that Colt is the manufacturer of the pistol and the model of it is Mark 4 and Series 80. The series 80 indicates that it was first introduced in the 1980's. The word "Mark" is the English way to denote a change and is often abbreviated with the letters "MK". The second line reads as follows, ""GOVERNMENT MODEL - 380 AUTO". This bottom line goes on to identify the model of this pistol as the Government model and that it is chambered for the .380 Automatic Colt Pistol cartridge.
The bottom left rear flat of the trigger guard on the left side of the pistol has been stamped with the letters "VP" inside of a triangle. This is Colt's Verified Proof mark and is added after the pistol has passed the final factory inspection. The upper front flat of the trigger guard on the right side of the pistol has the letter "N" stamped on it. I believe that this is possibly the identifying letter of the factory worker who assembled this pistol, but as of this writing I am unclear of the true meaning of this mark.