Ok. Thanks. I did finally manage to find some photos of similar pieces on the web. Seeing as how I am new to Breitling and to the hobby of selling watches, what is the best source for finding out the authenticity of this thing?

There's a couple of clues this might not be an original Breitling. The dial does appear to have some age to it in certain areas like the sub registers. The center and main numbers though look to have been redone at some point. Now that the dial has made one curious, you can look at the back of the watch and see no Breitling reference number, or at least a serial number, which would help authenticate the piece. Lastly, looking at the Venus 170 movements fit into the case it would look like the case is larger than your normally small 30mm - 35mm cases typical of Breitling during the 1930's and 40's. It was rare to see a Breitling case larger than 35mm during this period and I've only seen a few. How wide is the case not counting the crown? We've seen a lot of watches, especially gold Chronographe Suisse, which have been modified to give the appearance of being Breitlings. This might be another.

I think Roff, that maybe the metal cover is the dust cover found on the Chronographe Suisse models,and not the inside of the 18k case back in picture No 4.

In which case we know that it's definitely wrong because Breitling never used double casebacks.