Yeah, sounds like it because the lady at Silver Lake Marina also told me she sees only 1 picnic table above water from her office window.
She also said, everyone pays $20 at the Marina, even if you just park and walk around their marina area, it's a park fee, not a launch fee.
So, basically you pay $20 for the park, and launch for free if you want.
And from your link, i got this, oh well.:
"Fishing - There are no City managed locations that allow fishing on Grapevine Lake at this time"