Help understanding "unusually talked about" transistor code markings
The trasistor's complete identifier is not just 2222 but 2N2222A.
The A may be not unimportant depending on the application. 
It tells about ranges of the \$h_{FE}\$, \$f_T\$ and others parameters. 
The 2N prefix is sometimes omitted because it is used only for 
transistors (another prefix 1N is used only for diodes as 
you may know from the famous 1N4148 diode) and it 
is assumed that is is clear that the device is a transistor.
BTW "spec" is not the right term. 
By "spec" I would rather understand the datasheet.
&nbsp; 3. and 4.: All the other characters have no general meaning.
I.e. it depends on the
manufacturer what they are used for. They may indicate the 
manufacturing batch oder the date/week of manufacturing etc.