Pre-CBS and CBS Stratocasters

Fender Stratocaster are guitars built from components stored on shelves or in bins and some parts might have been fabricated many months before assembly. So, on the Vintage Stratocasters, the date on the body usually does not coincide with that on the neck and most of the time there is a gap of at least one, two or three months and, in few cases, this gap could be even of one year!
Moreover, at Fender nothing was ever wasted: if there was anything left in stock, it was used; if a certain component was not available, one compatible was found because production had to go on. Consequently, it is possible to find pots much more older, Black Bottom pickups in 1967, body of one year and neck or pickguard of another, etc...
Therefore, in general, you have to analyze each single piece (headstock, fretboard, bridge, etc), have at least an idea of the period to which the guitar under consideration belongs, look for the dates possibly placed on the neck, on the body, on the pickups and, only at the end, analyze the pots and the serial number, as it does not always manage to give us an exact indication of the year of production because it does not always increase perfectly linearly over time. However, collectors take as point of reference for dating the date placed on the neck heel, when present.
Moreover, at Fender nothing was ever wasted: if there was anything left in stock, it was used; if a certain component was not available, one compatible was found because production had to go on. Consequently, it is possible to find pots much more older, Black Bottom pickups in 1967, body of one year and neck or pickguard of another, etc...
Therefore, in general, you have to analyze each single piece (headstock, fretboard, bridge, etc), have at least an idea of the period to which the guitar under consideration belongs, look for the dates possibly placed on the neck, on the body, on the pickups and, only at the end, analyze the pots and the serial number, as it does not always manage to give us an exact indication of the year of production because it does not always increase perfectly linearly over time. However, collectors take as point of reference for dating the date placed on the neck heel, when present.
Modern Stratocaster
Even for the Stratocasters built from the '80s onwards the most common mistake is to date them only according to the serial number, mainly because exceptions are not few (just think of the serial "E4", "N9", "SE" or "MSN"). In this case also the date to consider is that on the neck. However, without disassembling the guitar, just knowing the model, its evolution and the changes it has undergone over the years, and comparing the conclusions with the serial number, you can get a good dating.