70 Hours PIC is a requirement to get the rating issued. You could do the training and even the test before you have 70 hours PIC, but most FTOs won't entertain this concept.
Quote from LASORS:
F3.2 REQUIREMENTS FOR THE ADDITION OF AN MEP (LAND) CLASS RATING
An applicant for a class rating for a single-pilot MEP (Land) aeroplane rating must produce evidence of having completed a minimum of 70 hours as pilot-in-command of aeroplanes.