I got a classical guitar from my dad's friend. I can't find any information online about the brand. In the hollow part of the guitar there's a sticker/piece of paper that reads "Shiro Kiboto fine guitars. Made in Japan. Model K370."

Does anyone know how good these guitars are? If they're not all that great, than I want to find another one.
I couldn't seem to find any info on that particular model, but the Shiro Kiboto guitars I did find seem to be pretty high quality, mostly from the '70s and '80s, but without being able to find that particular model, I can't tell for sure. One main feature that will almost always distinguish a cheap guitar from a more quality guitar is the top (the part with the soundhole); on a cheap guitar it'll usually be made from laminate woods, and on a more quality one it should be solid (made of a single piece of wood), because the solid wood will open up over time and sound better and better, whereas laminate will sound virtually the same forever. Here are a couple links that'll help you determine whether the top is laminate or solid, as well as some other useful tips for finding out the quality of a guitar:

Hope this was helpful!