You don't necessarily need it but it's very much recommended. If you know how to use ADB (Android Debug Bridge) then maybe you can install the mod without having to install TWRP recovery first because there are tutorials out there on the internet that tell how to boot into recovery mode using command prompts. But if not, it is safer just for you to install TWRP recovery first before installing the mod so that if anything goes wrong while flashing or after flashing, all you have to do is just boot directly into recovery mode and uninstall the mod.