You can get quite a lot just standing at the bar watching the bartender do the thing. Almost nobody considers this top secret, and actual inter4st maybe combined with a nice tip after the first round will go far.
As for "why to ingredients change?", it usually comes down to availability. They ran out of some stuff, usually because it didn't show up when it was supposed to, And maybe a gally-mate made a replacement. The substituting "cinnamon syrup" for "spiced brown sugar syrup" above seems like a case where a batch pf replacement just got brewed up, and it's close enough. We don't have to take a drink off the menu just because three gallons of syrup (wholesale price US$35) wasn't available.