Yes you will need a new roll pin. Once you remove the old one it will not fit properly afterwards.
If you are going to remove the roll pin use a roll pin punch and not a regular punch or the pin may start bending in on itself and will be a PITA to get out.
Ruger should sell a replacement. It will cost more than one from a hardware store, but you can be sure it will be the correct size and of the proper material.
Note: I am not sure if that pin can be driven through as I don't own an LCP. If it cannot then it will require a special pin extractor. The other option would be to drill the pin out. Drilling the pin out isn't something to take lightly, it could result in a few problems. Unless you have a drill press and a proper set of tools to handle such a thing it is ill advised.
As a rule removing the firing pin from a slide is a once and a while operation and not considered a part of regular maintenance.