is gluten free the same as wheat free

Not necessarily.

It is possible to have wheat-based items which contain no gluten (or only a tiny tiny amount - some gluten-intolerant people can cope with this trace) e.g. 'washed' wheat starch, glucose derived from wheat etc.

Similarly there is gluten in barley and rye (and a similar protein in oats), so just because a product is wheat-free, it does not necessarily mean that it is gluten-free.