Note on the first photo how the edge (chamfer) on the jewel hole is gone, this is because the bridge has been ground down so a new caliber number could be engraved, also note how shallow the engraving is. A 552 is a much easier movement to come by than a 551 so this is likely what was used to create this monster.
Second photos shows how it should look.
View attachment 6955
View attachment 6956
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