There are more photos of this Constellation on ebay, where it is for sale, but, although the seller states it is a Cal 564 and a 168018 case back, there are no photographs showing these. The same seller is also auctioning a Seamaster DeVille whose dial is amazingly similar to that on the Constellation, which rather supports the 'redone dial' view expressed by werdna77 and OmegaBear above.
Click to expand...