No, it also depends on effects like the pressure from the solar wind and outgassing. Outgassing is caused by water on the side facing the sun evaporating, emitting a gentle pressure away from the sun. If the object is rotating, the force pushes at an angle to the sun because the outgassing rate lags insolation due to the surface water's thermal mass (ie, each point on the surface continues to evaporate for a while after its apparent sunset.)

The effects aren't significant for planets, but they are for asteroids. It seemed more significant for Oumuamua than most, suggesting a high surface area to volume ratio.

I thought outgassing and solar wind was only really relevant when applied for a long time over many periods of an orbit? Would it have a significant impact on a one-time hyperbolic trajectory like this one?

In fact, one of the things proposed in the article is that the object is a light sail being accelerated by the sun.

And its speed!

Well, yes. I guess I was talking more on the lines of acceleration and deviations from a straight line trajectory :)