I do think it is recommended to meditate but it’s certainly not necesairy. There are a lot of people who can WILD and LD without meditation. (Link to The BIG meditation as a LD Aid topic)
That mantra does help in remembering your dreams. An important thing is also to keep a notebook and a pen besides your bed. So you can write down your dreams immediately if you remember them.If you want more tips on remembering dreams you could read the big remembering dreams topic 