Agreed, 154. As stated in another post, I think the ad features the solid gold model and the gold filled variant would possibly have a slightly plainer dial, maybe a "snob" factor, maybe a way to identify between the two models without having to take the case back off.
Also, the owner in his update states it is 19K, and in another post I have seen the same thing. It may be that the numbers have been mis-identified by the owners, or the number has been mis-struck, as we so often see in case numbers, especially as the ads state that it is in fact 18K "25 year" gold filled, but without pictures this is only my opinion, and maybe others will disagree.
EDIT:- Also the owner states 16 jewels, but the ad says 15, so maybe they looked without a loupe and it is hard to see properly sometimes the small numbers and letters on these tiny movements and they may be mistaken.