I replaced all four rollers (as they came in a kit of four), although only one of them was clearly bad (the bearing was shot and the roller had at least one flat spot).
The dryer is 10+ years old and in otherwise good shape. I followed one of several very good YouTube videos on how to take it apart and replace the rollers. It's rather involved and takes a few hours to do a good job, mainly because 70% of the entire dryer needs to be disassembled (including removing the drum). You may be surprised at how much lint was in the dryer cavity. Spending about 30 minutes vacuuming it all out (and blowing out other areas such as the motor with a compressor) is essential, as leaving all the dust and lint in place could certainly create a fire hazard (especially with a gas dryer).
The entire job took a few hours, but it's now running as quiet as the day it was installed. Very happy with the rollers and new lint filter; they're perfect.