Hi Ian,
the Mk.IIs are a bit odd in the whole GT40 pantheon. They were built up in the USA rather than at Slough in the UK so tend to be fitted with American sourced parts.
The rear lights on the Mk.II (and the Mk.IV as far as I know) are from a 1960/61 Chevy Corvair (no idea why they used GM parts
http://www.gt40s.com/forum/images/smilies/confused.gif 
)
The gauges on the Mk.II are Stewart Warner/Jones as well rather than the UK Smiths sourced ones.