I'm not an expert at reading manuscripts. However, I wonder if someone could check the transcription for Rev 15:3 in GA 452. The existing transcription shows "μωυσεως του δουλου του θυ". However, in looking at the actual manuscript, it seems like it reads "μωυσεως δουλου του θυ". Also, the ECM collation for this verse lists GA 452 as not having του before δουλου.

Hi Jeff - I have checked the manuscript and can confirm that both you and the ECM are correct, with no του before δουλου on folio 315v line 20:

δουσι⟦ν⟧ την ωδην Μωυσε⟦ω⟧ος δουλου του Θ͞Υ̅·

If you click where it says "Apokalypse Edition" on the transcription page, you'll find an alternative transcription which has it correct, along with a few other improvements.