I cannot give a precise answer, but the load should be OK. I can provide information from Quickload, which is a computer simulation program which PREDICTS internal ballistic information. I repeat, PREDICTS. This is NOT experimental data. Information is for a barrel length of 4".

Load: 141 grain Lead bullet, 3.0 grains Unique (no choice of 140 grain bullet available)
MV=677 f/s, Peak chamber pressure = 9506 psi@ 0.3 milliseconds after ignition

Load: 121 grain Lead bullet, 3.0 grains Unique. (no choice of 125 grain bullet available)
MV = 722 f/s, Peak chamber pressure = 9654 psi@ 0.3 milliseconds after ignition

The SAAMI maximum allowable average peak chamber pressure for the .38 S&W is 17,000 psi by the piezo chamber pressure gauge method, but I suspect the manufacturers keep it well below that level.

Note that it appears that the calculated peak chamber pressure for the heavier bullet is actually a bit less than for the lighter bullet at the same propellant charge, so if the 125 grain bullet load is OK, as it has proven to be for me, then a 140 grain bullet should also be OK.