SND,
I have flown at least 4 different aeroplanes in the last 18 months which had neither colour, nor lettering suggesting the required fuel type... Stickers fade / get destroyed and seem seldom replaced by some owners / maintenance facilities.
This type of attention to detail is often also reflected on the inside of the planes, where the interior is falling apart, the seats are damp / wet due to the seals not being watertight anymore, instruments are only partially working yet still carried... I actually remember my entire left side being soaked and partially frozen after going through a raincloud on the way to VFR on top. They are called spam cans for a reason - and that is my reason for not flying in these particular machines anymore.
But that was a very good idea!