This sounds right to me. I personally know 4 people from non top-10 LACs who attend top-20 econ PhD programs. These people had high GPAs and personal LORs, but otherwise their applications were probably similar to their current classmates.
Basically, I don't think it hurts you much when the adcom reads "college" and not "university." Although, it seems that certain application deficiencies (ie unknown rec writers, no previous graduate coursework) correlate with attending a LAC. I think LAC applicants have some advantages as well: RA opportunities (no grad students around), TA opportunities, personal relationships with professors.
By the way, I personally know 10 people from top-20 LACs who attend top-20 econ PhD programs.