Probably not, but that is an integral part of the definition of a theory. Observations show that objects are behaving differently than, in this case, known (and to a large extent proven) physics can can describe. The result is either the known physics (in this case basic gravity) is wrong, or something else with currently unobservable mass is in play in the observations.
This theory relies on well known laws of gravitational attraction, but observations said there ain't enough mass to do what has been repeatedly observed. So either apples fall up in some places, or there is more mass than what can be observed. The theory is that there is more mass than could be observed.
Now, through new methods, inferences, or whatever (I'm not a cosmologist, astrophysicist, or even very cosmopolitan) researchers think they have "seen" dark matter.
These results support the theory. If they had been different, they could have forced a change in the theory.
And, that's what it's all about..
Sometimes they see whatever will put the theory together, not matter how absurd.