How do I identify the SMD component marked as !3S 4?
The bars on the top of the S and 4 mean "Non Lead-Free Marking".
Production year is 2005, week 4.

The dot of the \$\underset{\bullet}{\vert}\$ mark is the pin 1 marking (do check the datasheet, it has a pin numbering as well).  

The combination of \$\underset{\bullet}{\vert}\$ means it was manufactured by a Philippine Subcontractor.

RoHS- Compliant Product Identification