What might be "coming out of the factory" is irrelevant. There is no way of knowing whether you will get one with a newer BIOS or one that's been sitting on a warehouse shelf for the last year. And if you live someplace other than the US or UK, the chances just increase especially if you are in a region with limited availability and sales.
That's another option as well, so good call on that. If, IF, you live somewhere that has trustworthy repair facilities you MAY be able to get a shop to update an older BIOS for you. Places like Microcenter and Fry's will usually do it for a small fee as well, but it's still an additional step and process that will be involved. You're simply not going to find ANY motherboard that is mini ITX and supports Ryzen out of the box unless it's X570 OR you're feeling lucky enough to roll the dice. The fact that mini ITX is a very niche market, means it's MUCH less likely you'll get a newly shipped board with a newer BIOS than if you were using a full sized ATX model that has a much faster turnover.