Originally Posted by TheOtherDave™
No. You will need a new gauge cluster..which means the entire gauge assembly that bolts and plugs into the dash.
The mechanical internals of the RS/LS/GS gauge cluster are different from those of the GSR and ITR. You cannot just swap gauge faces.
Seriously, your dealing with two different types of transmissions that have slightly different gearing that make the speeds calibrated to the car. If you don't change them out it will be off but who knows by how much. If you want to do the math go for it.