If you're intending to grind the rest of the damaged cutter off check for major damage first. Not uncommon on saws as large as yours to also crack the rest of the cutter down to the rivet (can be very hard to see and will bust later when you least expect it). If I were you I would replace the damaged cutter with a simple preset and tiestrap so that that section of the chain ends up missing a cutter (you won't notice). In my case I would replace it with a new cutter as I have a heap of them
Ideally if getting it replaced you should use the same brand and style of chain/cutter but this isn't really necessary.
All 3/8" brands of chain I've tried have interchangable presets/tiestraps with the exception of the "odd" Windsor preset that seems too large for any chain other than Windsor (got me beat this one?).
If it is a .404" chain both Windsor and Stihl are different to Oregon, Carlton, etc and their presets/tiestraps are not interchangable due to different sized rivets.