A reference number tells you what a watch is. It does not tell you what it is worth.

The three things dealers price

Condition comes first, and specifically whether the case has been polished. Sharp, unpolished lugs cannot be restored once they are gone, which is why original case geometry commands a premium no service can recreate. Second is the paperwork: the original certificate, the dated stamp, the service history. Third is provenance, which matters enormously at the top of the market and barely at all at the bottom.

On vintage pieces a fourth factor sits above all of them, which is the dial. A redialled watch is a different asset from an untouched one, whatever the case says.

What it means for an allocator

The premium for a complete, honest example is not sentiment. It is liquidity. The buyer at the other end of your eventual sale faces the same verification problem you did, and a full set removes it for them. That is why the spread between a full set and a bare watch widens when the market softens: in a thin market only the easy things sell. Buy the documentation, not the discount.