It is a known dulcimer maxim that the larger the interior volume of the instrument, the more bass/baritone/guitar-like the sound; conversely a dulcimer of the same basic size with a smaller volume will have a more traditional "high silvery" sound. The way most dulcimers add to the deeper sound is by increasing the depth of the sides. Shape (hourglass vs teardrop vs TMB) has nothing to do with the sound here; only the interior volume.
The dimensions of the June Apple are given as 1-3/4" x 6-1/4" x 35-1/2"
So although it's only 6-1/4" wide, it's 1-3/4" deep, and multiplied out, that gives you 388 cu. in. of interior body.
Compare that to my traditional Virginia Hogfiddle which is 1-1/8" x 5-1/4" x 35-1/4", or 208 cu. in.
Then compare those to a more or less standard McSpadden at 3" x 7" x 36" = 756 cu. in., which has a more modern "guitar-like" sound.
So... compared to most common dulcimers, the June Apple model will have a "more traditional" sound, certainly.