How to identify a real 3705 vs a 3706 with DLC treatment?

Hello, a first time poster looking for some advice!

I have found a seller offering a 3705 ceramic pilot, and would like to find out if there's any way to differentiate one of these from a 3706 with a DLC coating. The reason I'm asking is that I was in a shop today and saw exactly that (labelled appropriately), and as far as I could tell it looked exactly the same as the real thing. It's got me a little worried about paying so much without being able to confirm the authenticity. Is there an obvious difference in the case serial numbers, or can you tell by opening the case back?

Thanks a lot!

I think that will be verry easy.
The reference 3706 never has been produced by IWC with a coating.
Therefore there is no black coated 3706. If you find one it is a fake or someone has coated the case later.

Sorry for the newbie question, but is the model number actually engraved on the watch somewhere? Looking at the 3706 that had an after market coating in the shop all I could see was the serial number, so it wasn't clear whether it was a 3705 or a 3706, aside from the store telling me.
As I understand it these two watches are identical aside from the case color/material, so if the coating makes the color identical as well how can I confirm which model it is?

The original refernce 3705 did have a case middle made out of black ceramic. Thisis no coating but a massive material.
The original reference 3706 did have a case middle out of steel. This steel never has been coated.
If there is a reference 3706 with a coating I would be verry carefull to buy it. The coating is defenatly not original IWC and no collector would accept such a modification. It might be possible that someone want to sell a 3706 as a searched reference 3705 (wich is much rarer and therefore much higher rated).
Is it possible to publish the case number which is engraved on the caseback ?

I think if you find the caseback to be "black" then you definitely have a modified or counterfeit 3705. Here's some pics for clarification.

the movement (notice the "lip" of the case:

and in this side view, you can see how the back plate is steel, not zirconium:

I hope that helps your decision.

Best,
Larry

Beautiful watch! The strap is great. Thanks for the pictures. It looks like there is a steel ring with the threads in it bonded to the ceramic case. Is that correct? That looks like the best way to identify the real thing. Too bad you have to open the case to tell.

The coating job on the one I saw in the store was well done. Only the case itself was coated, so the case back was still steel...it looked exactly like your watch from the outside.

Unfortunately I don't have the serial numbers for either watch. I might be able to get them though. Would there be an obvious difference in the numbers?