Yep, the bare metal is fine, but in the photos of your turret it appears to be rather dark, like gunmetal.
The pics of the real turret appear to be the 'Loch Ness' Wellington, which I hope to see next month. This was an earlier Mark, with the two-gun rear turret, but shows well the colour of the bare metal.
No rush for the turret pics Andy, and I have some external shots of a complete (Lanc) rar turret on a 'jig' at DX if you need them.