Correct. I thought you get apply for a BG in Disneyland or DCA at opening time regardless, as long as you were checked into the park. Nope. You HAVE to be in Disneyland Park, not DCA to apply for the BG. When I tried, it said:
“Not so fast! You and all members of your group must be in the correct park to join a boarding group.”
I was pretty bummed out but luckily we got to ride it the day before. Makes for a good excuse to go back and ride ROTR again and also… Haunted Mansion Classic. The last three times I’ve been to Disney, Haunted Mansion has been closed or has the Nightmare Before Christmas theme (ugh)