We are doing a remodel on a house that has a brick exterior facade over CMU walls. We are only doing interior work so do not know what is going on between the them(gap or no gap). We have removed some interior wall coverings and exposed the inside of the CMU and I am wondering if it would be a good idea to paint the interior of the block with a masonry waterproofing paint before re-insulating and drywall. It seems like the potential for moisture movement is there but I am not seeing any real evidence of it. The interior framing is furring shimmed off and attached to the block. I am planning to insulate with mineral wool insulation and was originally thinking that I should leave the assembly the way it is for fear of concentrating any moisture migration into areas of the block that I cannot access to coat. 
Thanks,
Mike