Two simple things to look for when identifying Third Reich pottery.
The first thing to do is ask the seller wether the transfer (eagle, makers mark & date) are sitting above the glaze. If it is above the glaze it is definately a fake. You can simply test this yourself by feeling it with your fingernail. Ask the seller to test it for you.
The fakers then got wise to this and then re-glazed over the transfer. To check this for yourself, hold the item at an angle so the transfer catches the light and using a magnifying glass you will see the re-glazing as slightly raised. Ask the seller to do the same and you should get a honest response from an honest seller.
The pottery itself will more than likely be genuine old pottery, but NOT Third Reich. There are lots of this rubbish about, and two simple questions can save you money and heartache.