That tent is old. Around 1980.
And it looks like the fabric has stains on it. However it is not very clear from the video.

The plus side for the age is that the fabric used in that period last longer than newer cotton. Because environmental regulations the old methods are not allowed anymore.

But the age also wonders how good the fabric still is. And you need to have some knowledge to know what to look for.
People offered me great tents in the past. And I said they are ready to be binned. You don’t want to camp in a tent with worn cotton. It can fail on you in the wind. And never impregnate. That is not bringing back any strength.