Case serial number positions on vintage Yacht Clubs

Does anyone know if all vintage Yacht Clubs had the case serial number on both the inside and outside of the case back, or if some only had it on the inside?

I have an 18K gold YC in practically as-new condition, but the only thing that makes me wonder if it might have been (very) professionally refinihsed is the lack of any numbers or markings on the outside of the case (other than the hallmarks on the back of the lugs). The serial number on the inside of the case back appears to date it to 1967 (so the first year of production for the Yacht Club). The movement number is from 1968, and interestingly on the inside of the case back, as well as the usual Swiss 18K hallmarks, there is a British (London) import hallmark from 1969.

Hi Neeb,

that is a good question. None of my Yacht Clubs has the case number on the outside.

br

Cromagnonman

Good to know! I have seen a few with numbers on the outside of the caseback, but my suspicion is that they are later and that the earliest ones lacked this.

Have you any pic's of the watches you've mentioned?

Yes I do, but I seem to be unable to upload them. They appear to upload and insert and then I get a message saying that "An HTTP error occurred during file upload (error status: 500)"....

I've tried uploading at a smaller file size.

I'll try going back to Flickr...

Here's the 18K one. I think this dial is pretty unusual, it's basically the 18K equivalent of the vertically brushed grey dial you get on some steel YCs. There are no markings on the case back:

Here are the markings on the inside case back. I think the serial number dates it to 1967. Notice the London import hallmark from 1969 on the right!

For comparison, here's my steel YC with the serial number on the outside of the case (as well as "Stainless "Steel":

Thank you Neeb...never seen a steel variant so marked and thought i would ask because some herberts have been yacht-club-ing similar models, doesnt look like you have any problems.

Hi. I've had three of them and as far as I remember none had the serial number on the outside.

This is all very reassuring. Before I bought the 18K watch above I asked the seller (a professional pre-owned watch retailer in London) whether it had been polished/refinished, and they said that they thought it had been. To be honest, though, I think I've got a fairly good eye for that kind of thing and it seems pretty much pristine to me. If it has been refinished it's been done so professionally that it's practically impossible to tell. I did wonder if maybe IWC themselves had refinished it. But other than the seller saying that they thought it had been (which may just have been covering their back), the only thing that made me suspect it is the lack of a serial number on the external case back. I have seen 18K YCs with serial numbers on the back. But if many/most lack this, I'm tempted now to think that my watch might be untouched.