I'm not too familiar with MAC foundations (since I don't use it) but I asked the MA one day what shade I would be for MAC foundation/concealer one day because I was curious and got 2 answers since she said that different products are slightly different in shades.
I use dior and I'm either a 200 or 300 for their different foundations, so the answer here is no, you might not be the same for all products from the same brand.