What works for a Platinum (and Ultimate!) member may not work for someone without that status; the Crown Lounge as an arrival lounge option seems now to be resticted to FB Platinums (and Ultimates) so it's no surprise at all that you were able to get in.

To the OP - try scanning your boarding pass at the lounge but I wouldn't fully expect you will be admitted upon arrival in Amsterdam from your (shorthaul?) feeder on the day before your transatlantic departure.

(As you'll obviously be lodging somewhere for the night upon arrival, I would think that heading straight to your accommodations would be a more preferable prospect than visiting the lounge)