There is no such thing.
You can't find registeel in Pokemon HeartGold.
You can find it in Pokemon Platinum, Pokemon Crystal, Pokemon HeartGold, and Pokemon SoulSilver.
unkowns {pokemon}
You cannot find Latios in Pokemon HeartGold unless you went on wi-fi and got the Enigma Stone
You can't
yes
trade
You can't
Just find them!
You can't do it.
Find and then catch
You can only find Skarmory in the Pokemon SoulSilver version.