Nope. Seeding Stargates =/= seeding life.
Name just one planet that the Ancients seeded that didn't have a stargate.
That's a fallacy.
A planet that's been seeded with life typically has a Stargate yes, but it doesn't imply the other way around. Basically, life seeded --> Stargate deposited, but Stargate deposited -/-> life seeded. What if they just dropped a Stargate on the surface and stopped there? Why keep going?
In fact, there is no mention of seeding life within that article at all; it's all about planting Stargates.
But obviously I can't find any examples of this since, of the 2 galaxies we've played in, both were seeded with life.
It's about both ships the unmanned seeder ship and the second one to follow up and explore the worlds seeded by stargates for some unfinished experiment.