Goofy and Donald met Ven for what couldn't have been more than five minutes a decade prior in a relatively uneventful meeting while they were concerned about King Mickey. The only reason They gave Ven the time of day in the first place was because he knew Mickey but were overall uninterested in him as a person. It's much like when they first met Sora, they weren't all that interested in him per se, they were just intested in the fact that he had "The Key" and Mickey ordered them to go where ever the key went.
Besides, when it came to apperances, KH2 as a whole was kind of...weird. It's like it wasn't sure certain characters where supposed to look like others or not. Canonically, Sora, Ven, Roxas, and Vanitas are supposed to like similar with a few variations, as well as Kairi, Namine, and Xion. The games (particularly KH2) only aknowledge this when it's convinient. e.g., I'm more baffled that Donald and Goofy, or even Sora himself, didn't point out that Roxas looked like Sora when they saw the picture of him.
Meanwhile, Aqua notices that Sora is the spitting image of Ven even though there's a good ten year or so age difference, lol.
KH is over all weird when it comes to this sort of thing so I think this is a case where it's probably better to not mind it much and chalk it up to the writters being lazy.