Only to the extent of saying it is 'alien'.
That doesn't strictly exclude either transhuman or post-human colonists or human made AI.
I don't doubt that there will be 'alien alien' stuff out there, but I also expect there to be 'not actually alien' archaeology, too.
And entirely dependent on if they discovered their own means of ftl travel. Its been around 1000 years since they left. So their travel distance depends on what relativistic speed the ship reached. And the bubble is only a few hundred light years across in diameter.
Relativity can be effectively ignored as regards their perceived time. Relativistic effects on time are only worthy of proper consideration as regards to the time taken to perform scientific research when the vessel is very close to light speed.
For example, travelling at 90% of the speed of light will have a x2.8 time dilation factor. That's considerable, you might think. But drop the speed to 2/3 of c and the time dilation is only about x1.3.
The problem being of course that we cannot attain even close to these speeds.
Unfortunately, one cannot just make a rocket and accelerate forever. The limit on velocity is mainly down to the rocket's exhaust velocity. Off the top of my head, I seem to recall that the current theoretical limit for a fusion rocket is .3c of velocity. Antimatter rockets can boost it to nearly half the speed of light, but that is still not fat enough for time dilation to make any effective difference. [assuming you an carry enough fuel, of course]
Outside the realms of complete fiction and a story device made for narrative reasons, I don't honestly swallow an isolated community on an ark 'realistically' having the tools and knowledge to invent FTL on their Jack Jones, without any scholastic input from the rest of humanity, using the limited tools and facilities they have available.
Consider just what proportion of all human research scientists are going to be on board any one ark vessel. Let's say humans have 'only' a million researchers in the field, out of a population of 20 billion [meaning 1 in 20,000 people works in the discipline]. If you put a thousand of them on the ark ship, that gives them a 'science power' which is a thousandth of the rest of humanity's AND is handicapped by lack of up to date peer papers to read, communication with the other 99.9% of scientists, and potentially limited resources.
Science generally progresses by sharing information, rather than in isolated communes.