I don't think the timing is odd at all. The Union Bears / Copland Collective have had numerous banners calling out the board, and stayed on at full-time on Sunday to call them out.
The UBs do have a beef with the board and it's up to individuals to decide whether that's a legitimate beef or not.
I think it's safe to say they'll have a presence at this demonstration and will be the vocal element.
They are well within their rights, as are any other Rangers fans to make their frustrations with the board known - better outside the ground prior to the game than inside during..
Some fans will agree with them, some fans won't and some will be apathetic about the whole episode.