Its actually in the Regulation not the AMC:
FCL.1030 Conduct of skill tests, proficiency checks and assessments of competence
(a) When conducting skill tests, proficiency checks and assessments of competence, examiners shall:
(2) verify that the applicant complies with all the qualification, training and experience requirements in this Part for the issue, revalidation or renewal of the licence, rating or certificate for which the skill test, proficiency check or assessment of competence is taken;
It hinges on whether the medical is a "qualification"!
MED.A.030 requires applicants for licences to hold a valid medical but makes no reference to renewal or revalidation.