Not really. No airplane was ever grounded by the FAA since the 1970s, when they grounded the McDonnell Douglas DC-10.

Since the merger, the FAA has grounded both of Boeing's new planes (The 787 Dreamliner and the 737 Max).

Boeing's safety record is objectively declining. They are shipping out airplanes with safety issues that are being found "in production". This is why their planes are being grounded (something that never happened to Boeing pre-merger).