Very interesting! I read that the current flagpole has been in place since 2009 and is made of douglas fir. Back in the day, if you wanted a flagpole you went to the places that made masts for ships, some of which were in Baltimore.
As a landlubber I might have known that “cross” was called a “yardarm”, but only from movies ;-) There’s a whole etiquette about how signal and other flags are flown from the yardarm. And I came across another question that appears to have a simple answer but an intriguing folklore: “What’s in the ball on top of a flagpole?”
https://www.usflagcompany.com/2017/06/whats-really-inside-flagpole-ball/