That's completely irrelevant. It's clearly saying they were there before satan was which proves Premill to be true. They were cast into lake at the Rev 19 second coming but satan was not cast into the lake until AFTER the thousand years. That proves they were in the lake LONG before satan will be cast into there.
No actually it isn't. Other translations say "And the devil, who deceived them, was thrown into the lake of burning sulfur, where the beast and the false prophet had been thrown. -- Revelation 20:10
If you do a search for 1000 years throughout scripture you will see it signfies a long period of time and not a literal 1000 years.
Psalm 90:4
Verse Concepts
For a thousand years in Your sight
Are like yesterday when it passes by,
Or as a watch in the night.
2 Peter 3:8
Verse Concepts
But do not let this one fact escape your notice, beloved, that with the Lord one day is like a thousand years, and a thousand years like one day.
Ecclesiastes 6:6
Verse Concepts
Even if the other man lives a thousand years twice and does not enjoy good things—do not all go to one place?”
Source: https://bible.knowing-jesus.com/topics/1000-Years-And-More