Personally, I doubt it.  I can't tell that you have any significant
gingival attachment loss.  I think it would be easier if this bothers
you so much  to do resin bonding or porcelain veneers on your central
incisors to attempt to fill that space.
    It may not be possible to fill the space entirely this way without
overbulking the teeth.  But I think a gingival graft is even less likely
to accomplish this.

Steve

Generally gaps between the teeth after closure of spaces between the teeth,
do not close well by grafting soft tissue.  Generally, this requires a
different contour to the restorations which fill the space between the
teeth.  There is a range of distance from the crest of the bone surrounding
the teeth that the gun tissue will be capable of growing to.  To close the
"black triangle" *usually* the dentist has to make sure that the "apical
extent of the proximal margin" is close enough to that bony crest.  If it is
further away (as it seems to be in your picture), then the soft tissues will
not grow to fill the space.  If grafted into the space, the gum tissues will
most likely shrink back down again.

Not a dentist, just another consumer.    Most people would be happy to have
teeth and gums that look like they are in as good a condition as yours are.
Do you have anything else to think about.    I would just worry about
keeping them that way for always.
Gail