Yes, I have used a TDS meter for salt measurements but I had to calibrate it for the salt range of the pool. You can do this with either calibration solutions or using a Taylor salt test kit to get the actual salt level of the pool and then adjusting the meter to read the same level.
But in reality, a meter should not be required because it really doesn't matter what the actual salt level is, only what the SWG unit thinks it is. As long as the SWG unit produces chlorine, that is all that matters. The only time a secondary measurement is useful is when you are trying to determine if a SWG cell is nearing end of life.