At first, Fender Stratocasters were fitted with brown “phone book” Cornell Dubilier .1MFD paper oil capacitors, recognizable by the writing “ZNW1P1 .1MFD 150VDC C-D”.  Brown capacitors were used until 1957, when Fender gradually switched to the white version.
In 1961, Fender started to replace phone book capacitors with 1MFD ocher-colored round ceramic capacitors, recognizable by the writings “SK .1X 50V”, used through all the '60s, although in 1962 paper oil capacitors were still used.
Around 1968, .05MFD capacitors were first used, in order to achieve a slightly brighter tone.  They had different shapes, but the most common were the yellow lentil shaped capacitors, recognizable by the writings “20% D .05 100V” or “80-20 D .05 50V”, and the polyester green chicklet capacitors by Nissei, which featured the marking “NISSEI .1K 100V” and were used only on 1968 Stratocasters.
Other capacitors were also used in the '70s, including cylindrical 1MFD caps.
In 1983, the Standard Stratocaster known as “2-Knob Stratocaster” was equipped with .022MFD capacitor. 
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'50s brown phone book paper-oil capacitor

1960 white phone book paper-oil capacitor

1963 ceramic capacitor

Lentil capacitor on a 1972 Stratocaster

1968 Nissei capacitor (Courtesy of Philippe Cabau)