I understand this as a mostly theoretical question. On the application layer, you don't select frequencies in Bluetooth, this is done by the Bluetooth stack, which uses frequency hopping, as mentioned by pancho_hideboo. You could however refer to a 2.4 GHz OEM protocol where specific channels are selected.
Technically, most 2.4 GHz front ends on the market have homodyne (zero IF) receivers, thus LO is equal to channel center frequency.