If it is anything like this https://www.sciencealert.com/it-s-official-the-definition-of-a-kilogram-has-changed 50m could have stretched or shrunk by a couple of mill, so, NO 50 metres is not necessarily 50 metres.
It’s a little early for the hard stuff, but I guess I can spike my coffee if we’re gonna get back at that game. SNORKEL!!!