gotta listen to my instincts...

so this isn't quite a plot-hole, I'd say it's more of an oversight on Carlito's part. When he's going to visit Kleinfeld in the hospital and he sees Vinny (I think that's his name) disguised as a policeman, the voiceover says "got to listen to my instincts, like the one telling me that face and that uniform don't go together". So he not only sees Vinny there, he also acknowledges that he looks out of place. Then, at most a couple of hours later at the club, he doesn't recognise Vinny and makes the "I haven't seen him lately" slip. Maybe he didn't recognise him out of uniform (including the hat which would have covered a lot of features), but I think it would have been easier to swallow if they'd just cut out that voiceover line at the hospital, or better still only shown Vinny when he came to "relieve" the officer outside Kleinfeld's room. And while they're at it they could have cut the bit when Saso tells Carlito that Pachenga's spying on them for Benny Blanco, which I know has already been discussed on other threads.