For the tribs, it certainly will help. But I don't think it's the silver bullet that it would be if it were 2 weeks later.
2 things are necessary to start a sizable run (more than the handful of fish poking there heads around now).
1. You need the lake temperature to come down. Signals to fishies out in the lake --> time to head to the tribs.
2. You need flow to allow them to get into the tribs and get upstream.
It's gotta happen in that order and getting #2 doesn't help a whole lot without #1 happening first. Normal lake temps are mid 60's at this time of year. We're still at 72 last I saw. 68 is regarded as a "magic" number to really get things moving. I don't know how magic it is but colder is definitely better.
If there were thousands of fish just waiting for high water to come in, they'd be cleaning up in the lake around the mouths of the creeks. They're not. They're picking up the very occasional fish just like the stream guys are doing in the lower ends. There aren't huge schools staging right now. The warm lake is why.
That said, yes, it's still better than NOT getting the rain. But for now I'm looking for those cool nights as the first priority, and we're getting them too, so things are looking up. But once the lakes get into the 60's THEN I'm watching for the big rain.
Tropical Storm Matthew is a potential silver bullet. It's still far out so track is very uncertain but currently on path to provide that silver bullet in just under 2 weeks. Hopefully it comes and by that time our lake temps are where they need to be.