Domestic US Flight- Infant?

my sister will be travelling with her 6 week old infant from SFO to PHL on 3-Apr, return 8-Apr. direct on US Airways

two questions:

1- are there bassinetts on this flight?  would she call to reserve a bulkhead?
2- does the infant need a photo id?

the infant does not have her own seat.

From their website:

"US Airways defines an infant as a child less than 2 years (24 months) of age. US Airways recommends traveling with a birth certificate for a lap child between the ages of 1 and 2."

On this page they have some information on flying domestically with infants flying in a parent lap, but it doesn't say anything about a bassinet being available.  You might call the airline to see if they have those on domestic flights or to at least confirm she'll have a bulkhead seat as it's more room and would be easier with a little one.

http://www.usairways.com/awa/content/traveltools/specialneeds/children.aspx