You sure, Rikk?
I don't think the naming template is stored as part of the external editor definition (see below). So Edit With will simply use the current value of the external editing filename in Preferences. You can see this if you swap between different external editor presets - the filename template stays the same.
John
s = {
id = "0FFFEF11-23FE-49F6-9B68-69160B39CB3F",
internalName = "Silver Efex Pro 2",
title = "Silver Efex Pro 2",
type = "ExternalEditor",
value = {
externalEditingFormat = "TIFF_None_16_ProPhotoRGB",
externalEditingFormat_dpi = 240,
externalEditorFullPath = "/Applications/Nik Collection/Silver Efex Pro 2.app",
},
version = 0,
}