As I don't keep BPs or snakes with similar needs, I don't ever see moldy branches, but that's certainly possible for yours. Up to you, but I'd try without coating, then if it
becomes an issue, get more branches & coat them. What you cannot (ie must not) do is kill the mold with diluted bleach if it appears, since the bleach fumes will stay IN
the wood, making it forever toxic for your snake to breathe...so if you get moldy branches, just pitch them & get new ones.