Mr. Schumann,
Welcome to the gang! I think you will get a lot of helpful ideas and can decide on one that fits you best. like Ron said, you might explain a little of what you want to accomplish. In my opinion, anyone wanting to build a longrifle will need some basic tools. Files, rasps, a mallet, a hacksaw and a few others. As far as chisels and gouges, almost everyone I know that builds longrifles will say a must will be a good set of quality (not necessarily expensive) straight chisels from 1/4” to 1” and even 1/8” if possible. You can find good ones like old Stanley ones on EBay at a good price. I have a set of the ones with translucent yellow and black handles that have served me well and keep a remarkably sharp edge. Other good ones may also be available when you look. As far as for carving curves for inletting locks, sideplates and anything else with curved inlets, that is where your gouges come into play. I have been to several classes and the instructor usually sends out a list of a couple of hundred dollars worth of speciality chisels and gouges to purchase but my experience is one rarely uses over a few of those recommended. Then I went to a class last fall and the instructor did not recommend a long list of chisels and gouges to my surprise. We went to a big box store and bought a dirt cheap set of very small screw drivers and proceeded in class to sharpen and reshape them into a miniature set of straight chisels ranging from less than 1/16” to around 1/4”. We proceeded to carve a very nice pattern on a curved piece of curly maple and it was amazing. Not a single gouge was used for the project. In conclusion, my experience and use has made me a believer, like Bob McBride said, that a few smaller gouges will do most anything you want. I find the Pfeil intermediate gouges like nos. 3, 5, 7 in smaller sizes from 2-5 mm will do about everything you want to do. Hope this helps and gives you another perspective. Good luck.
elkhorne