Do you lose treasures when you upgrade?

This may sound like a stupid question for those who have already been through this, but do you lose your treasure when you upgrade? I haven't upgraded to Baron yet because I'm still in my safe week but have enough points for Viscount and I am not sure whether I should have one nugget ready or two.

Thanks in advance for your help.

when u meat the requirments of the general upgrade task the treasure will disapear but the perstige wont