Flowguard Gold is marked with a yellow strip and marked also marked with the brand name. Flowguard Gold is a brand name created by Lubrizol to market its CPVC resin. Several different manufactures make pipe and fittings under the Flowguard Gold name. Flowguard Gold is not substantially different from any other brand of CPVC with equivalent ratings and listings. You will pay a little extra for the Flowguard Gold brand name.
That being said, I would make sure whatever brand you use has UPC and NSF-pw listings. These are independent labs/agencies that check that the pipe/fittings meet national water safety and plumbing codes. The agencies audit the companies that make the pipe and fittings and verify the quality of the product with testing.