Should funeral flowers be delivered the day of or the day before?

I need to send flowers, and the viewing is on Monday. However, since Monday is Labor Day, I’m coming across a lot of online flower delivery sites that do not give Monday as an option. If I want to go with one of these, is it okay to deliver the flowers the day before the viewing? Is this usually what people do, or do they have them delivered the morning of the viewing? (Thanks in advance)