Hi there! The Gilded Bloodscale is indeed an Eastern- the reason for the infobox error was because it used to be listed as Western until the spriter corrected us on it. The page itself has always been in the Eastern category. If you're unsure, always check to see what the more commonly listed item is rather than the least- in this case, the Dragon Sub-Types page and the page categories both showed Eastern, so the infobox was wrong (updated now).
No, it's good to do something when you spot a mistake, it's what helps the wiki be as good as it can :) I was just offering feedback in case it comes up again in the future and an error needs to be fixed!