Once you paid FSD already, you can book for FSD hardware upgrade for free.
This upgrade is separate from Infotainment so you make sure you ask for both Infotainment and FSD Computer.
It's at:
Upgrade your Infotainment system to access new features, and for a more advanced and smoother user experience.
www.tesla.com
"This upgrade is available for $2,250 plus applicable tax, including installation, for vehicles equipped with Autopilot Computer 2.0 or 2.5 and for $1,750 plus applicable tax, including installation, for all other vehicles. Owners may confirm Autopilot Computer type by selecting ‘Controls’ > ‘Software’ > ‘Additional Vehicle Information’ on the touchscreen."
"The Radio Upgrade costs an additional $500 plus applicable tax and there is no difference in price if you have the Radio Upgrade and Infotainment Upgrade installed separately or together."
Not automatically. You need to ask both to be done or otherwise, they think you only want Infotainment this time.
Since you paid FSD already,
HW3 is free.
Infotainment is extra charge.