This is an additional specification recommendation, which means that people who write clients should not rely on a server that always sends 005. Thus, you can either make it an optional optimization for stacking / unpacking the mode, or make your bot work only with servers that send 005 when processing connections.
As I said, I don’t think I have ever used an IRC network in the main thread that did not send 005 while processing the connection. I know that I don’t speak much, and I don’t even have any data to support this.