Revealing mistake: In one of the shots of a newspaper you see a serious grammatical error for a headline. The use of "it's" instead of "its". It was something to the effect of "Ahead of it's Time". Forgivable for a note left by a character, but a mistake that real newspapers just don't make. Just FYI: The actual headline is "Nexim Announces It's Answer to ARC's Living Display". (00:11:40)
Revealing mistake: During the close-up of the gas canisters, the condensation is running upwards and "into" the valve. (01:31:10)
Answer: He does recognize Rachel from the party as well as when he when he saw her at Allcom. The only things he doesn't remember are the last three years of his life since starting the project. So, while he does remember her, the three years they spent together while at Allcom are a total blank. This recognition is shown when he meets with Porter who helps him escape.
But later, when he is going through her stuff, he says he doesn't remember her. Also, if he did remember her, he would have known it wasn't her when the imposter was in the restaurant (also no need to have the imposter try to dress like her either).