Your measurement implies that the range of answers is 128.6 mL to 128.8 mL.
If you do not state explicitly the range of uncertainty (e.g., ± 0.5 mL), the implied range of uncertainty is ±1 in the last significant digit.
Thus, a reading of 128.7 mL implies that the volume is 128.7 mL ± 0.1 mL.
