Info on v39

Happy birthday to me My wife found me a Vendo Model F39B and I need some information.  The machine is in like new condition and works great.  I first thought that it must be a restoration but I cannot find anything on it that doesn't seem to be original.  The person she got it from said he found it in an old store and it was in it's original condition.  The serial number data plate has an F407 stamped in it followed by 64572.  The 64572 looks like it was manufactured with the plate.  How can I tell if any restoration has been done on it?  Also can anyone tell me anything about the serial number and what is a Model F39B versus say a model 39?  Thanks.