Only 1 datapoint, but I got a OWB on a points stay as a HH Gold last September. The app said I was initially upgraded to the Endless Lagoon View [hilltop] villa, but I was very pleasantly surprised at check-in. I arrived midweek on a Tuesday, and I definitely noticed the resort got busier by Friday. I suspect if I had arrived on a Friday/Saturday/Sunday, the OWB upgrade wouldn't have happened with a lot guests arriving and leaving on weekends. Prior to Bora Bora, we stayed 3 nights at the Hilton Tahiti over the [US/Canadian] Labor Day weekend, and I also noticed a significant drop-off in occupancy in guests there by Monday [a good number of those guests were heading to or coming back from the Conrad BB]. I think a lot of folks from North America had wrapped up their summer vacations.
Note, I don't remember any construction going on last September, so that might also affect the supply of villas for upgrades available. YMMV ¯\_(ツ)_/¯