Hi, you should be able to look up the silk colour at the end of the strings to figure out what strings you have, and some lookup sites also show the tension (e.g. the D'addario site)
https://gollihurmusic.com/string-identification-chart/?srsltid=AfmBOooatO-fJJAUc10SynBPGqEaKyyOm6AepzTS_2RkOJRadf2nBDz2
There's not really a wrong type to put on, but some strings might need a tweak e.g. gut strings sometimes need wider nut grooves. And lower tension strings have more movement so you might need to raise the action slightly if the strings are hitting the neck.