This guide was not complied by me. This is from All About Pocket Knives

Tang Shown: 3 Line Arch Stamp

Time Estimate: Early 1900's; roughly 1902-1915

Tang Shown: 4 Line Stamp (Also Shown Lower on This Page) 

• First 3 Lines are identical; 4th is a bonus because is sports the manufacture year + the U.S,A
• Used on Camillus knives for a very brief period

Tang Shown: 3 Line Straight Stamp

Time Estimate: Roughly 1916-Early 1930's

Tang Shown: 4 Line Stamp

Time Estimate: Early 1930's to mid 1940's

Tang Shown: Note Details. Similar to Others.

• Non-Italic Font
• Length of line between "CAMILLUS" and "NEW YORK" is shorter than others
• Line is also shorter than on others such as on the tang that is pictured next

Time Estimate: 1946-1950

Tang Shown: Note Details. Again, similarities to others. 

• Non-Italic
• underline Extends the Full length of the letter in the word "CAMILLUS"

Time Estimate:1960-Late 1970's

Tang Shown: Note Details. Similar to Others.

• Underline extends the full length of the letters in the word "CAMILLUS"
• Periods between the U.S.A

Time Estimate: Later 1970's into the 1980's

Tang Shown: Most Recent 

Time Estimate: 1989- until Bankruptcy in 2007 (emerged from bankruptcy in 2009)