Yes, it has to be skilled work experience. Working in a call centre is not considered skilled unless he's doing technical support or if he's a call centre supervisor. A bank teller or clerk is not skilled but a loan officer, clerk supervisor etc. is skilled. Look at
http://www5.hrsdc.gc.ca/NOC/English/NOC/2006/Welcome.aspx to look for job titles, descriptions and to find out if they are skilled. You will see it from the 4 digit number.
If the first digit is 0 like 0122, it's a manager job and is skilled
If the first digit is not 0 but the 2nd digit is 1, 2 or 3 like 1111 or 1212 it's a skill level A or B type job and is skilled.
If the first digit is not 0 but the 2nd digit is 4, 5 or 6 like 1433, then it's a skill level C or D type job and is not considered skilled.
You could even have a skilled job by working in McDonalds and similar places. Looking at
http://www5.hrsdc.gc.ca/NOC/English/NOC/2006/QuickSearch.aspx?val65=fast+food you can see 0631 Restaurant manager is absolutely skilled, 6212 Shift manager is also skilled, 6641 food counter attendant, not skilled.