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No there isn't, at least not that helps in this case: the resistor that's built in is in series with the built-in led only. It's not in series with an led that you attach externally. Check the schematic:https://www.arduino.cc/en/uploads/Main/Arduino_Uno_Rev3-schematic.pdf
The 4k7 and the 2k2 resistors are a voltage divider to drop the 5V output from the Uno's Tx pin to a lower voltage for the Bluetooth module which is not 5V tolerant. (5x 4.7/(4.7+2.2) = 3.4V)
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