DisplaySearch estimate that the plastic OLED display used in the Apple Watch costs more than $27 (this is the production cost, not the display price). They say it is difficult to know for sure as the cost is highly dependent on yield rates at LG Display's fab and they do not know it yet. They assume a 60% yield rate for the $27 estimation.
The $27 estimate includes the plastic AMOLED module, the touch panel interface and the cover glass (sapphire or glass, depends on the Watch model).
Several readers complained to me lately that I claimed that the Apple Watch uses an AMOLED display, but did not give any evidence. In my original post I quoted Jennifer Colegrove from Touch Display Research. Now we also got confirmation from DisplaySearch.
If that's still not enough, you can hop over to LG Display's official newsroom. On the top newsreel, you can see the latest report - "Apple Watch to come with AMOLED panels from LG Display". Strangely, this links to an unrelated post on Digitimes about AUO's LCD supply deal to Sony's latest wearable. But I think LGD will not have used such a headline if it weren't true...