Original Canon C300 Mark II owners with the clam-shell monitor can easily add Touch Focus with the Touch Focus Upgrade Kit.
CANON C300 MARK II EF TOUCH FOCUS UPGRADE KIT FOR ORIGINAL C300 MARK II CAMERAS $1299
Canon C300 Mark II EF Touch Focus Upgrade Kit Includes the following items:
Canon LM-V1, Touchscreen LCD 2417C001
CANON MA-400 MICROPHONE ADAPTER 0873C001
Mount To Shoe Adapters
Micro Ball Head
You’ll re-use the UN-5 cables that were supplied with the C300 Mark II.
You’ll need to update the C300 Mark II firmware to enable support for the LM-V1:
Canon C300 Mark II Firmware Version 1.1.1.1 or 1.1.2.1.00
Here’s a video from Canon that shows the Canon C300 Mark II Touch Focus: