Will a seat from a 2007 scream eagle street glide fit on a 2010 street glide?

 

No. Not without signifigant modification. Frame change in 09

 

No, but doesn't have anything to do with the 09 and up frame change, its the 08 6-gallon tank that changed the seats. You can use an 08 and up seat on your newer bike (except for Corbin, they have special 08 seats and 09-up seats).