On the left side of the breach... if there is one. Early Model 33's did not have a serial number.
About $70.
32-33 years old
SN's were not required before 1968
Without the serial number, the question can not be answered.
33-59
Approximately 33-34 years old
No known published serial number data. 50-125 USD or so
Serial look up will give you year but the barrel code will also give you the month. http://www.remingtonsociety.com/rsa/questions/barrelcodes
33
Depending on condition, up to $150.
32-33 years old.
Go to remington.com.