As a new modder myself, I cannot stress this enough: take this slow. Soldering/drilling/whatever else you are planning on doing is NOT as easy as it looks. Soldering takes time to learn, and the best way to learn is by practicing on something inexpensive. Try soldering wires together first so you get the feel for your iron and what it takes to get the solder to melt and stick to your wires.
I jumped in head first and tried putting together a 5v mod with no previous soldering experience. Let me just say I have a very useless plastic box with wires sticking out it sitting in my drawer. I took a step back and watched some soldering videos and decided to take a stab at a 3.7v mod. That was much easier to put together and took very little time to complete.
Go slow when it comes to modding. Take your time and don't give up if your first mod doesn't work or has a lot of flaws.
But to answer your question, yes. The mod kits come with everything you need to get the job done aside from the tools needed.
Good luck!