Could drinking kombucha tea once, day before blood work was done, raised my GGT to 157 following day?

That'd be a first. You're the guy with the elevated RDW, correct? Some folks always run a high GGT -- it's genetic. Your ropinirole isn't noted for raising GGT but medications can do this unpredictably. More worrisome causes of high GGT include liver tumors -- these would typically also elevate your alkaline phosphatase.