As stated above, it's rare for a US/Canadian Marriott/Renaissance to have the lounges open on the weekends except maybe for breakfast. The breakfast is hit or miss, even for a given property. If they have a lot of elites or people paying for concierge in advance, they might do breakfast on one or both days of the weekend. However, you might get breakfast one Saturday, and the next the lounge might be closed.

I don't think I've seen more than a handful that have the lounges open on Friday or Saturday nights.