What's up with this caseback? Any ideas?

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Somebody modified the case-back for some reason that is hard to comprehend.

 

I know! I crave to understand the history of this watch.

 

You can own it, but you can never understand it.

It's an extreme version of all the posts about frankenized Speedmasters with service parts where people speculate about how a given watch came to be in its current state.

But I totally get it.

 

The inner case seems to have an ancient piece of tape/adhesive. Presumably to keep the holes "plugged". At least, I think that's what it is.

 

OK, should we make guesses?

It seems that maybe someone added through holes to screw something onto the back. There is a mark on the back suggesting this. Perhaps they wanted to mount the watch on something other than a watch strap.

 

Yes, I agree. It was clearly mounted to something.

 

I'm surprised that there is enough clearance inside the back for screw-heads.

 

Possibly the holes are tapped, but there seem to be circular marks surround the holes on the inside, as if there were screw-heads or washers. Not sure.

 

Here is a slightly higher quality image:

 

Yup, looks like something was mounted to the case back. Probably in order to mount to something else. Whatever it was, it was there for a long time. It looks like some corrosion had started under whatever was there.

 

Some idiot thought it was a screw back case.

 

Sold for 2.5K. That's all of it

 

What makes you think it sold?

 

Snap back case. That would be interesting.

 

Interesting price. Especially given the dial. The back can be repaired.

 

38mm case. Calibre 83. Introduced in 1935 up to 1947. 69,600 were made. 6,000 were used in the WWW Mark 10 military watches. (Source: OF)