1955 Rolex Sharks Teeth - Date

[ChicagoWatchGuy]

Hi All, wondering if anyone knows a bit more about this watch...below is what I was informed:

1955:
Tru-Date (but does not say on the watch)
Ref #6530.11.55 inside / 6530 outside
Serial # 90xxx (which does not make sense)…I would have to take the band off
25 jewel automatic movement #552161 – note it winds both ways
Caliber #1030
Round screw back case, black gilt dial, luminous dot and dart markers, dauphine hands, center sweep second hand, alternating red/black roulette date, smooth bezel, SS rolex riveted oyster bracelet, folding clasp circa 1955

It is in MINT condition - just wondering why it does not have "date or tru-date" on this style...not sure? Looks around, found similar just different and none with the oyster band. Thanks,