Are you meaning fielding forward-arc instead of just boresights?
In which case, they could do it not too far off crusade era, but probably won't for a long time; the only reason why they couldn't is the size of the cannon they're trying to fit - almost all beam weapons are technical descendants of copies of centauri battle lasers flogged by the centauri or nicked by the narn (so if you had technology equivalent to the centauri or better you could probably do it if you put your mind to it).
These copies aren't quite as good - either you get much less powerful versions (combat lasers/burst beams) or you get equivalent power, but the thing's now so bulky it doesn't get the same arcs of fire (medium laser/heavy laser).
However, the EA, having gone in a big way for the boresight heavy guns has now surpassed the original centauri designs in power and have now progressed to even bigger guns (Neutron weapons/particle beams) so you're going to have to be proportionally more advanced to do so - big wide-arc triple damage laser-type guns are the exclusive province of the Minbari so far*.....which the EA is some way off even in crusade era..
* The narn mag gun is not a laser. And I've never understood why it has the beam trait.
