Yeah, you definitely want to separate the them, especially since you don’t know the sex.
Scenario one: you have two males. As they mature they’ll become highly territorial and fights are extremely likely. Permanent injury and even death can be the result.
Scenario two: you have a male and female. When they reach puberty the female will be under ongoing stress from the male constantly trying to mate with her. And if a female mates too young there are numerous health issues that can result. And if they’re brother and sister...not a clutch of eggs any breeder aspires to produce.
Scenario three: two females. This is the only scenario in which two dragons can cohabitate. But even in this instance, you would need to watch for signs of dominance and intimidation like a hawk: one dragon sitting on top of the other while basking, one dragon always hiding, one dragon too intimidated by the other to eat, one dragon growing at a much healthier clip. If you don’t know what to look for, you may wind up with one dragon in a constant state of stress. I’ve met a lot of respected breeders that house multiple female dragons together without issue, but the circumstances are incredibly specific (cages much larger than the average pet owner’s, multiple basking spots so there isn’t a competition for resources, fed separately, etc.). So while two adult females being housed together isn’t completely unheard of, the circumstances needed for it to be successful seem to require an advanced level of setup and behavioral observation, and there’s still no guarantee that just because they’re two females they won’t fight or engage in bullying.
The good news is that because beardies are solitary by nature, there’s no downside to separating them. In captivity their social personality is the result of interactions with their humans. If both your dragons are given lots of love, attention, and a large enclosure, they’ll never be lonely in their own cages.