How do you know the chassis number immediately?

Noticed on the 288 GTO thread and a few others, many of the members on here will see a picture of a car and know the chassis number immediately. Often times the picture doesnt show any discerning features and even more mysteriously in some cases doesnt even show a reg number, so I'm really dumbfounded how you know what the chassis number is immediately! Is there something I'm missing in being able to recognise a car?

 

Quite a few people track the history of many Ferraris, so if there's even a SLIGHT hint of which vehicle it could be (i.e.: "This Ferrari is located in Manchester, UK" or: "this is the one that raced at xxxxxx in 19xx"), in many cases, lots of people here will be able to ID it.

 

I'm gonna bump this thread, since the thread I'm linking to below is a perfect example of how the answer to the OP's question can come about...


http://ferrarichat.com/forum/showthread.php?t=382448