Can't agree more. With the advance in technology, everything can be forged. College graduation certificates, passports, watch case, serial numbers, gold seals inside watch cases (I have seen this in flesh - a 18k Cartier white gold Baignoire with bracelet, I was told only the movement and the box are original, the case, the bracelet, the zeals and number? No) ..., you name it.
That said, It's not uncommon to see "open" Patek certificates going around in the secondary market, especially for those references produced before the late 90s. When I bought my first Patek back in 1997, the AD suggested that they leave the paper not dated, and in case there's any problem with the watch, they could extend the warranty period for me. Don't really know this can be encouraged. Not quite moral, but it's a "service" to their customers. So, the Certificate of Origin in my vault is still with any date, but it does have the AD's company chop.
However, I think we should all be careful when buying newer models. As all the community members here know, Patek has been very careful in controlling flipping of their watches (through controlling those loyal ADs), starting with the period when 3712 was launched, so there should not be, in theory, many open papers for recent models in circulation.
There are numerous watch shows and jewel shows in Hong Kong, where I reside. So, I buy only the seller, not the watch, and I believe I won't have the luck to get any deals that are too good to be true. I never won a lottery anyway.
Francis
... but mostly no name, very seldom no date.
And for more recent models (especially the ones still in production), it is very difficult to find watches in the secondary market with open papers (no name, no date).
If you knew how to look, Patek uses numerical codes to indicate the date of when a Certificate of Origin was printed - not just when the watch was sold. That needs to be consistent with the date of sale as well as the date of manufacture. Cross-referencing that to when a watch was in production (assuming it is discontinued) helps root out forged papers.
But if you purchase anything I'd make sure I have someone from Patek or an AD take a second look at the paperwork and the timepiece to make sure everything is OK. Can't be too careful.
Not wanted to get off topic but curious about this issue of anonymity. I have sold several watches over the years that had my name on the COO and never thought twice about it. We sell cars and houses with our names on the registration and deed (some perhaps even less expensive than our watches!) and I don't think most would lose sleep over it. Why the privacy concern over having your name on the watch certificate and known to the new owner?
It had long been my understanding that 'open papers' were more often than not the result of a grey market sale with most AD insisting on filling these out at the time of purchase, although admittedly I had never specifically asked to have this omitted. Would purchasing new from an AD without him filling in the paperwork cause any problems should you require any warrantee service?
I guess I've always been leery of open papers for the above reasons, but I'm eager to learn from this forum and very curious to see how the majority feel about this. Not wanting to highjack this thread please accept my apology if this violates forum etiquette.
Anonymity is important to me. No reason that a future owner should know who I am, and possibly find my home address and target me for a burglary. Paranoid perhaps, sure, but these are high value items.
I have purchased all my watches new from AD, and I ask they all come with open papers, and my AD conveniently “forgot” to fill in my name…. On a couple of them.
I’ve since had both Philippe Stern and Thierry Stern personally hand-sign my papers, and they didn’t seem to care less when I gave them the open papers to autograph. This was around 5 or 6 or so years back, and I think the practice may be stricter today.
(removed my AD's name in the cert)

