>>1991232Yes, they are. If you turn them in or out they will either move the derailleurs position in high gears or low gears. Normally new derailleurs have a L or H, L for the big gears, H for the small, but your might not have them labelled. You want the derailleur to be in line with what ever gear its in, if its not it will skip and not pedal properly.
You also have this screw/ housing thingy that will tension or loosen and can be used to adjust the derailleur as well, you want the cable to be firm in the highest gear, not loose or way tight.
There's also a good chance you bent the derailleur so if it looks like its sewed to one side at an angle, just bend it back, its soft metal and can always be bent again if you mess up.