I don't think it has anything to do with HO.
While shopping for a CTD in 03 I found both 47 and 48's in the CA SO models.
03 was the year they depleted 47 stock however I am pretty sure that in other states where you could order an HO model with an auto it would have got the 48.
So if you have an 03 HO its a 48 and if its an 03 non HO auto it could be either.