The laser is the same in all of the Hitachi as well as Samsung version 360 drives, and there are 2 versions also, the SF-HD63 and SF-HD67 and either one can be used as a replacement.
If ya want to buy a whole new drive, for whatever reason, then yes you can just swap out lasers and that it, but buying just the laser would be cheaper.
The Hitachi drive also has an issue with the spindle motor, and that could be the cause as well. It gets full of gunk and doesn't spin properly, just cleaning and relubing it fixes that problem though. If ya still are set to get a whole new drive you can get any version Hitachi and then just swap over the Logic board from yours into the new one, thus turning the new one into your drive without having to mess with FW flashing and such.