Yes, as there could be dust or left over residue from something that could prevent the silicone from bonding. Also its not like it takes alot of time just a few seconds of wipping each piece of glass. Also after you silicone (min 28 hours) you will need want to get some cloth rags and soak them with water to clean off any residue from the silicone, then I would suggest filling the tank with water and letting it soak for 24 hours, and then another quick wip of a clean water soaked rag, and it should be fine.
It may sound like alot of work but its better to be safe than sorry.