Hey,
Unlike the (L), (ZL), (ZR) and (-) buttons, both the (+) and (R) buttons are not on separate tiny circuit boards connected through a flat cable to the main JoyCon board. Instead they’re soldered directly to the board (the (+) in the front and the (R) in the Top-Left on the back of the board).
Just changing the button is not easy as you need to remove the old one and solder a new one but it can be a headache because of the size and position of it.
If you can find a R-Joycon selling for 10-20$ that have problems with anything but the mainboard then you can just exchange it from one to the other.
If the shell colour is different then the colour it shows on the switch will be the Original Joycon shell colour. You have software online that you can use to change it to your original joycon colour (you need to connect the joycon to the pc via bluetooth) so when you slide it into the switch or go to the controller screen it shows the right one.