this is my first forum post of any kind,

I bought an m&p off of an individual, when i started getting familiar with the weapon my first thought was that the trigger had been worked on.
This bad boy has the lightest trigger and no manual safety, i'm not that familiar with pistols,i've always just owned guns for hunting purposes.
but now i have my ccw and would like to at least have pistol that i can carry with a round in the chamber.
just wanting to know if i should send it to s&w and have a new slide w/safety or take it to a gun smith and have them look at it?

What do you mean by light? 3#, 4#, 6#? If you have access to a trigger pull scale check it to see what the actual pull weight is. A stock M&P trigger should be around 6.5#, about what a good double action revolver would have. The M&P are a well tested very safe gun that will not fire unless the trigger is pulled. Keep in mind your brain and your trigger finger are any guns best safeties. If you are diligent about keeping your booger hook off of the trigger until you are ready to fire the gun and always carry in a good holster that covers the trigger you should have no problems.

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Life Member B.A.S.S., NAFC

Your own words confirm you need to take the gun to someone who is qualified to check the condition of the gun and be sure it has not been dangerously modified. Like Dick asked, how light?

No offense, but you seriously need to take a good basic pistol course such as the NRA course. Then use your new knowledge to pick the gun you want.

Unless that used gun was free, you are going to put too much money into it, and are going to be upside down on it in value. A $400 used gun with $200 added work (and shipping) is still a $400 used gun.You would be far ahead trading it for what you want.

The slide has nothing to do with the thumb safety on M&Ps. If you want one with a safety you'll need to trade yours in on one.

It's appears that the installation of a manual safety on your M&P is NOT what is of primary concern, at this point in time. Even though you have obtained your ccw/cpl, by your own admission, the fact that you do not have any pistol experience to speak of, speaks volumes about whether you should even be packing...again, at this point in time. I wholeheartedly agree with both Dick and OKFC, that you need to get some instruction and (lots of) gun handling/practice time before you even think about "going outside" with your pistol strapped on, let alone, altering your weapon.

Please, PLEASE!, do yourself, your friends/family and your community a huge favor/service, by getting trained, educated and familiarized with your weapon. With all due candor and respect, it sounds like you do not know what you do not know yet.

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MotorCityGun

First start with the easiest solution. Ask the previous owner if they had a trigger job. Next if you don't get an answer have the trigger weight tested. If its the normal 6.5lb trigger your fine. If its less you need a gunsmith to correct it before ccw. Ask your local gun dealer for a gunsmith. They will know some. You can even have a 10lb trigger installed. No need for a safety. Just learn the gun by dry firing it, then live fire. The trigger has a built in safety. You just need to get comfortable with the gun. It won't go off if you don't pull the trigger. Practice handling the unloaded gun learning not to touch the trigger.