Sorry. Timed out before I finished editing.
rob
The answer to your problem is at the bottom of this page.
Found that wrestling with my own question. My photo has the following code:
2308224131 Polaroid 3.
According to the above site, an 11 digit code is pre-1980 and starts with the prototype number. Post-1980 film starts with the month number and has 12 digits and the prototype code follows the Polaroid logo. I can't find prototype a prototype code 23. This site suggests that Prototype 3 code indicates Spectra / 600 Hybrid-4-RA film which is a wider format. My photo is a standard square format. However, an individual in the picture is wearing Walkman-type headphones placing it post 1982.