Man, that is a killer watch! Judging by the discoloration on the dial, my guess would be this watch has been together a very long time as seen. Dating by movement code, and the fact it is only a year off from the ad, I would be inclined to call her a 1928; pending Alex's s/n check.
Minutes track and discoloration is a match to the case opening, and the ad is pretty weak on dial detail. Personally, I would leave her as-is. It would be a shame to modify her based on a single identified example (this one) and a guess when it's possible the single ad may show artistic license. If you look at the dial numbers font, they appear to me to be a close match the artist rendition ad, noting the "8" and "3" in particular.
Not implying the dial is indeed original or replacement - not enough data for me to say one way or the other.
1928 Olivia pending date check of case