If you go to the S&W website and choose the model you have, it will say.
The standard (Non-Mass Compliant) weight is approximately 6.5 Lbs +/-.
I believe ALL the Apex kits, reduce trigger weight to 5Lbs or less.
If not to decrease trigger pull, Why do you want to install an Apex Kit?
If it's due to 'grittiness', you can smooth everything up by doing the Burwell's DIY M&P Trigger Job.
S&W M&P Trigger Job