Is the MSP430-GBP board flashable trough a Launchpad's EZ-FET module ? (SWB lines)
( I mean EZ-FET from MSP430FR4133 Launchpad ot similar EZ-FET interface)
I hope you mean "MSP430-GBD" - if I'm correct then yes, you can program it via SBW. The main chip of "MSP430-GBD" is MSP430F2274A, which supports SBW. You can find the required signals at the JTAG connector.