Yes and no...the magazine will obviously play a roll in the function of a 1911. The only way I would consider needing to run several hundred rounds through a specific magazine would be for carry. I never had problems with the ACT mag that came with my RI 1911. In fact, it functioned fine in all my .45's.
I'm not sure why you think you need the 500 round factory FMJ break in either, but that's spending a pretty penny for something completely unnecessary. I know my RI never even had a factory round through it. Invest in molds and lead and shoot more....if you run into some kind of problem you can't sort through then buy a box or 3 of factory ammo.