Yes, if you can do an upload, it would be cool. So if i understand you right, you were there and saw it in reality? What did the owner say about how and where he did get it? That should be the key about the condition of the item. If he did not dig it from earth everything could have happened with the hatch. So maybe there is a chance of a later chemical reaction of the colour - as i wrote before - but it is sure, that the colour in that turquise condition in 1944/45 never would have been used as camouflage colour or passed the Heeresabnahmestelle. Germans were not crazy, guys.