Shinichi's/Conan's thoughts from 969 have so little context—clearly, he's not at the revelation point (and neither is Ran—I wonder if she and Shinichi/Conan will have a simultaneous revelation, given that they're both keen on remembering meeting Masumi). Maybe his memory is fuzzy enough (probably not the most apt word choice, on my part) that he isn't remembering Shukichi right. He didn't immediately connect Mary to the woman, even though that's the first person that should've jumped to his mind, so who knows how accurate his memories are, before his revelation point?
We probably will have to wait until 972 (presuming this case ends at 971) to get confirmation on whether this character is Shukichi or not.