Yes,that is true. For your 4th plus FPs you must make FPs at a kiosk (although there are inconsistent reports of concierges at resorts making number 4).
Although I always go to rope drop at first part, and save my FPs for the 2nd park when it will be a busier time of day.
The issue seems to be if there will be any FPs left at the second park that are worth getting ( usually only yes at MK), and do you really need them at rope drop? I usually don’t use FPs at EP (since the only attraction I really enjoy that needs one is Saorin) but I always use FPs at HS ( since I can easily find three attractions I enjoy that usually have long waits).