I don't think so. Just because a court orders something done, it doesn't always mean it happens immediately. It has to be implemented. The rate remains 55c until, I imagine, the USPS itself lowers the rate. Whenever that will be.
The 'Forever' stamps will then be sold at the lower rate, but of course any of those stamps will meet the First Class rate no matter what it is, high or low. If you use stamps with values on them, you still need to put 55c worth of stamps on the letter until the rate is officially lowered. If you're still using up those 3c sheets of stamps you bought back in the 1950s, that will require 19 stamps! That's a lot of Statues of Liberty.
It's not easy to find reliable, up-to-date information about current first class postal rates around the world, but just as an example, China typically charges "around" 20c for a first class letter at the cheaper end of the spectrum (but wages there are pretty darn low) while I think it's Norway that has the highest first class rates in the world. The last time I looked Norway was charging nearly $1.50 to mail a first class letter. It's all those fjords they have to swim across, I imagine. So 55c doesn't seem so awful.