They kind've have the Mage's weakness in that area, only with endurance rather than willpower.
They also get ten siders for hp so the loss isn't so much of a problem. Members of the Brotherhood of the Crystal Star only get 4 siders and they pay an endurance cost for spells too. Think how they must feel.
To play a Dwarf Gunner properly you should probably prioritise ability scores as follows:
1: Constitution
2: Strength (for encumbrance & the occassional bit of rough stuff if things get a little bit too close)
3: Intelligence (the mechanistic/scientific mind), Wisdom (Common Sense & general survival & awareness), & Dexterity (shooty stuff). Optionaly Dexterity could easily be considered as priority 2 up there with (or even above) strength.
4: Charisma (and maybe move Intelligence or Wisdom down with charisma if you've had a load of low rolls).
I suppose it'll depend a bit on how your GM allows you to generate ability scores. The best (pre d20) ability score rolling system I ever saw was a bit complicated but always worked out in your favour.
You rolled 7d6 and dropped the lowest one (giving you the highest 6 of 7).
You then assigned 1 (and only 1) of the die rolls to each ability score.
This process was then repeated twice more (thus allowing for some control but also a random factor). By the end of it you would have assigned the highest 18 of 21d6 to 6 different ability scores in batches of 6, each batch being assigned before the next bunch were rolled, thus no prior knowledge of future rolls would shape the distribution of the early rolls.
It's actualy quite a nice system (and gives better averages than the popular "roll the best 3 of 4 7 times, drop the lowest and put them where you want" method and by better averages I don't mean higher, I mean more average).
Oddly enough the pre generated Gunner in Dawn of Destruction has a pretty high constitution and his dexterity is only 10. He actualy fits my above priorities list fairly well when all his ability scores are taken into account. Scary, huh?