I looked at 'em side-by-side, not a bad match at all. (I recognized the name Gordon Lightfoot but wouldn't have been able to venture a guess at what he looks like, so I'm just going by pics.)
Similarities:
The hair (curly, perm-y)
The mustache
The straight-across eyebrows
Distance from eyebrows to hairline
Cheekbones
Width of face
Length, width, and straightness of nose
Plus, I found him by looking for a list of 70's singer/ songwriters, on which all the other guys in the pic appeared (a list of 12 or so).
I couldn't find a picture of Gordon laughing/ grinning (and couldn't make 2Packs' link work, maybe that is one), but stuff seems to line up really well.