Yes, There is a filter and it doesn't matter whether your week is Platinum or Silver. I have several timeshare intervals of varying quality, and they all pull differently. It is most evident during the Flexchange period when the only factor is supposed to be quality in determining what resorts you can pull.
The other day, I had a conversation with an II rep regarding the quality filter for my Equivest Vacation and Travel Club points. With one of my other resorts, I was able to pull Bluebeard's Beach Club. I could not pull it with EVTC. I found that interesting, given that it was an EVTC resort by special arrangement up until this year. The II Rep told me it was a lesser quality resort, and that is why I couldn't pull with EVTC. Go figure.