Recreating RSE NPC in-game trade mail on Switch FR/LG via ACE?

[superzman300]

Hello, I hope I'm posting this in the right section. If I'm not, please redirect me to the proper location.

I’m trying to recreate the original RSE NPC in-game trade mail on Switch FR/LG using ACE, as faithfully as possible. I want to try to recreate these NPC-made messages as a small preservation project with the help of ACE, considering we might not get the Hoenn games on Switch.

Pkhex shows the message (as the proper values representing the easy chat words), the author data, and mail type/ featured Pokemon. However, under Author, I can't figure out the two-number pairing that PKHeX shows for an extracted mail message. For example, looking at RoC's github Ruby save file (which has both the NPC Skitty and Mailbox message data- see below), the message for DARRELL's Skitty holding Glitter Mail shows the paring 0 and 54024. These are not the TID/ SID pairing for said Skitty- those are 02259 (TID) and 00000 (SID). I suspect 0 and 54024 are some kind of separate hidden author ID/ mail record data, but I'm not sure.

Does anyone know exactly what those two numbers represent, and whether there is a way to reproduce them through ACE on the Switch ports of Fire Red/ Leaf Green? I want create a replica of in-game trade NPC mail, but can't fully do so without accounting for this mystery. Thank you for your help and clarification!

Screenshot for reference: