I can say with all certainty that this is confusing for everyone because it is my opinion that the Dot locator (For Mention) having a double use/meaning tends to muddy the waters quite a bit on this topic.
Let me give you my interpretation (please correct me if I am wrong) and perhaps that will better frame my question. The Dot Locator has 2 uses:
Use 1 is for establishing a frame of reference when reading braille that is free floating in space to allow the reader to correctly interpret the braille text.
Use 2 is for a first time appearance of a transcriber created symbol in the braille text make a clear distinction apart from any text they've seen so far and establishing it as a symbol from that point forward.
The base question then is this, are the symbols in the key deserving of the Use 2 versions or the (For Mention) aspect of the dot locator even though they are transcriber generated?