Your request makes little sense since for LCD panels connected directly to the beaglebone there is no auto-detection of any kind (unlike HDMI) hence all of the relevant parameters for the specific lcd panel you're using need to be configured in the overlay. Whether it uses 16 or 24 data lines is only a small part of that.
As Mala Dies pointed out there are a bunch of overlays you could use as example. Of the ones that use 24-bit color, BB-BONE-NH7C-01-A0.src looks the simplest (although it still includes pwm backlight and an i2c touchscreen).
Matthijs