Angel describes Buffy character wise as being American, with natural blonde hair and blue eyes because that is the way creator of the character Joss Whedon intended Buffy Summers to look like, and not by the way the actresses who played her did. Sarah Michelle Gellar's eyes are green and had to dye her dark brunette hair for the role of Buffy, followed by Kristy Swanson the original Buffy who has brown eyes. But the character itself Buffy Summers has rightfully been described in the way she was designed to look, blonde with blue eyes.
After the bomb goes of and Spike is upset about his destroyed jacket he got after he killed Nikki Wood in 1977 in a New York subway car he claims he has been wearing the jacket for over 30 years which isn't possible since this episode is set in 2004 which mean he could only have been wearing the jacket for 27 years maximum.