Yes this will be a spare just in case.
I did verify the correct part number with the company on Ebay.
It is Dayco 5061000
and it cost me $23.90 with no tax and free shipping.
If you buy it from Ford or a parts shop if they have it it will cost $50-$97 plus tax so for the small investment it's worth it to me.
FYI and info
I will be close to 50,000 miles on my 2012 this year so that is why I'm getting it.
Now this is for the 2012 V10 with AC which relates to probably all Georgetown in the past 4-5 years.
The belt is attached to the engine crank shaft pulley and turn water pump, alternator, radiator fan and AC compressor.
So if you break it or starts slipping because of grease etc you will have an issue while on the road.
If you are interested here is the Ebay link
Serpentine Belt Dayco 5061000 | eBay