It's probably worth it in that case (only), then again to get right to the top of Le Morne, one needs either a long ladder to walk across, or as some other trekking companies are offering, using a line to pull oneself across a cleft.
There are many other treks which can be done in Mauritius without the need for a guide, just a little tenacity and some balls of steel ;-)
Here are some examples I have attempted:
Lion Mountain, Tamarin Mountain, Piton de La Petite Riviere Noire, Le Pouce, Pieter Both, Signal Mountain, Corps de Garde, Nicoliere Mountain.
You can get more details from the book "Mountains of Mauritius, A Climber's guide" by Robert Marsh. It is out of print, but you can get photocopies in the libraries around Mauritius.