Does this indicate at all that she should lay soon?
Maybe, maybe not.
Mating is often more about dominance that fertilizing eggs, though a mature rooster should be worrying about dominance a lot less than an immature cockerel would. I've seen a 13 week old pullet willingly squat for a 13 week old cockerel. She did not start to lay for another 6 to 8 weeks. She was being submissive to his dominance, which is a bit unusual even for a pullet a month older than her. So it is not a guarantee that she will drop an egg tomorrow or the next day.
Still its a good sign. A good mature rooster should not be mating a pullet that isn't close to ready. It happens, some mature roosters aren't that good. Hens give off some signs that the eggs need to be fertilized that the rooster can recognize, things like the comb and wattles turning bright red. These are the ones a good one should be turning his attention to.
Also, a pullet is more likely to willingly submit to a rooster when she is ready to lay. Until then they tend to run away.
All in all, it is a good sign. But it is not a guarantee.