Duraluminium is an alloy of aluminium that was used for Landrovers, and a
number of other vehicles and aircraft skins in England and possibly other
countries. The colours are almost identical as are most aluminium alloys,
with the biggest difference between them being the way Americans spell
aluminium wrong.
If the alloy is anodised, then the colour may be different with a range of
blues, golds, etc available. Aluminium will oxidise quiclky and build up a
surface layer of oxide coating that looks a little white compared to a
mirror like finish.
In current times there are over sixty common alloys of aluminium made by the
larger companies, and a number of other specialist ones for special
purposes. Some of them are used for corrosion resistance and some of them
have higher strength, some of them handle heat better than others. Pure
aliminium is lighter coloured and very soft and silicon is added to many
castings at about 10 to 14 percent to make it harder while extruded parts
like spars are about 1/2 to 1 percent silicon. The silicon will make the
alloy a little darker but most people will not notice this. Other elements
like magnesium, copper, manganese are added to improve the properties of the
alloy.
As you have two colours available, I'd be inclined to paint cast parts like
brackets in the darker colour and sheet panels in the duraluminium colour,
but this could be adapted to suit your preferences or any notes you have
after viewing real equipment displays. Newer equipment will be a little
cleaner while used equipment will be a little more weathered.
Hope this helps,
Peter