I have a client that will complete their one year of skilled experience in Canada in mid-December. CEC allows for a reasonable amount of vacation time in their qualifies for the work experience requirement. However, the client has only taken 4 days off. In light of the above, do you think a CEC file can be submitted a couple of weeks prior to the 52 weeks if the applicant did not take any vacation? I’m sure the answer is no, but wanted to double check, since things are a bit different with Express Entry.

Under CEC, full-time work is calculated based on number of months of full time employment, assuming the person works 30 hours minimum per week.

The reason this is so is due to a combination of the Regulations and the Policy Manual. The wording of s.87.1(2) of the Regulations states as follows:
(2) A foreign national is a member of the Canadian experience class if
(a) they have acquired in Canada, within the three years before the date on which their application for permanent residence is made, at least one year of full-time work experience, or the equivalent in part-time work experience, in one or more occupations that are listed in Skill Type 0 Management Occupations or Skill Level A or B of the National Occupational Classification matrix, exclusive of restricted occupations
In its Policy Manual, IRCC interprets this to mean a person needs to complete 12 months of experience, so an applicant needs to go through the full 52 weeks even if she reached the equivalent number of annual work hours earlier due to not taking holidays.
Applicants must have at least 12 months of full-time, Canadian skilled work experience (or the equivalent in part-time work experience).