Usually, two dashes in the Service Factor mean that it is close to 1.0 which is indicative of an uprated motor. However, the amps suggest a full rated motor so that part is uncertain. I couldn't find a cross reference but did you ask the dealers if they cross referenced the part # with the motors or did they guess?

Also, 56y frame has a motor body 1/2" wider in diameter than the 48y but in most cases they are interchangable.