Yes, the flowers, trees, and bones are all different for each player. The flowers are only in the secret door with the DELTARUNE symbol, the red trees outside in waterfall, and bones on benches or boxes in Snowdin. You can also just guess the last number since that would be the only thing you're missing. Also, you have to wait like 5 seconds for the door to open if you got it right, so don't put another number while it's opening.
