Garchomp and Fire Fang

I have a question that I have had trouble answering. According to sites like Serebii and Bulbapedia Garchomp learns Fire Fang at level 1. It doesn't make much sense to me so I want to know if I can give a heart scale to the move relearner in Gen 6 or 7 and they will teach Garchomp Fire Fang? And also would Fire Blast be better in terms of avoiding things like Rocky Helmet or Iron Barbs or to do more damage. Any input is appreciated.

Garchomp has 80 base Special Attack, which is sad. For reference, Smoochum is 85. However, Mega-Garchomp gets a boost to 120, which puts it on par with several Legendaries. If you wanted to do a Special Attacker or Mixed Attacker set, then I can see Fire Blast being an acceptable move. However, without the full EV investment, I think you are better off taking the recoil damage. Plus most Pokemon with Iron Barbs are Steel Types and would not last long against a Fire Fang Garchomp with full EV investment.

Ok, thank you for the input. Also Garchomp can learn Fire Fang via the move relearner by using a heart scale right?

No idea.

Ok, thanks anyway for the move set input. After I evolve a Garchomp I'll take it to a move relearner and see if I can teach it Fire Fang.