I've a customer claiming that the default function for F5 key on his mac is to launch the widgets screen.
Is this true? Can be an old apple keyboard or an old OS X such as Snow Leopard with this default setting?
Was always F4, as far as I can recall.
My 08 keyboard has it printed on the key itself - same layout as this picture
Prior to the introduction of the aluminium keyboard in 2007, there were no icons printed on the keys, so it would be hard to say for certain - but as Snow Leopard was 2009, it would be unlikely it would be anywhere other than where the printed key indicates on anything later than Leopard, 10.5, which would have been roughly coincidental to the introduction of that keyboard design.
The Evolution Of Apple Design Between 1977-2008 would appear to support that.
The F4 key was assigned to launching the Widgets screen on Leopard/Snow Leopard era keyboards, it has since been assigned to Launchpad. As it's the fifth key along your customer could possibly be confusing it for F5...