No. Because "dis" has another meaning besides "the opposite of."
The online dictionaries were no help here, except that dictionary.com pointed me to the excellent free resource, the Online Etymology Dictionary created by a guy named Douglas Harper in his spare time.
In addition to the usual meaning of "dis-" there is another meaning according to the OED's entry:
...also "exceedingly, utterly," from PIE *dis- "apart, asunder" (cf. Old English te-, Old Saxon ti-, Old High German ze-, German zer-).PIE is: "Proto-Indo-European, the hypothetical reconstructed ancestral language of the Indo-European family. The time scale is much debated, but the most recent date proposed for it is about 5,500 years ago. "
The PIE root is a secondary form of *dwis- and thus is related to Latin bis "twice" (originally *dvis) and to duo, on notion of "two ways, in twain."
The word "gruntle" does exist in original form from 15th century Middle English and means "to grumble." So being disgruntled means to be very gruntled, not the opposite of gruntled, and so no, you don't want to be gruntled. Although obviously disgruntled is even worse.
But really, could a word that sounds like "gruntled" ever mean anything close to "satisfied"?