[dragon1]

We know from "In the Beginning" that the G'quan has been in service from at least the Minbari war. During this period it would be very likely that she would be armed with plasma cannons (blue burst) like in the game.

From season 2 footage though we see the primary bolt weaponry as a dual firing pulse cannons (yellow as opposed to blue bursts).
I would immagine that these dual pulse cannons saw an increase in range and rate of fire and a distinct decrease of firepower.

Is there any possibility in the future of seeing the G'Quan with these guns?

[Col. Fishguts]

G'Quan's armarment changed everytime you looked at it, especially in the early seasons. They finally settled with the 2 big red beams, as has TBP.

Of course you're free to change the weapons in FRED.

[Sigma957]

Weapons systems for the G'Quan will remain the same but as Col has said use Fred to change the weapons.

[-Norbert-]

And I also think that it was an error, that both a G'Quan and a Vorchan where in ITB.

[dragon1]

Why would a Vorchan in 2245 be a mistake? JMS simply established the Vorchan and G'Quan classes in the canon as existing in or before the Earth-Minbari war. In addition, we know from interviews from JMS that the Hyperion-class starships were old when the Minbari war started and they were still in service as late as 2281.

As for the weapons systems of the G'Quan, go back and watch the second season, they appear to be consistent throughout.

2 Heavy laser cannons that can fire within a rather large arc
At least 3 dual pulse cannons
1 Energy mine launcher

The pulse cannons targeted both Centauri fighters and a Battle Cruiser (in the episode "And now for a word"). The pulse cannons always fired linked (2 bolts per volley, typically 5 volleys per gun)

The heavy lasers could fire linked, like they did against the Shadows at Gorash VII, or individually, like they did against the Centauri Battle Cruiser in "And now for a word"

[Bri_Dog]

Wasn't the G'Quan one of the first ships the Narn built after the Centauri left? If so then there's no reason why they wouldn't have some during the E-M war.

[Trivial Psychic]

The Th'Nor is the oldest cap-ship in the narn navy.  With the possible exception of the Bin'Tak, the G'Quan is the newest, but there's no reason to believe that it wasn't in service during the E-M war.  Its only 10 years after all.

[-Norbert-]

Then why didn't they use G'Quan when they attacked Gorash in "Midnight at the firing line"?

[karajorma]

Didn't need them

Besides the Centauri might have noticed if the Narn started gathering G'Quan's for an attack. Maybe they didn't keep an eye on what the smaller ships were up to.

[Fury]

Actually the most likely reason is that the CGI team did not have G'Quan finished at the time.

[dragon1]

The Narn utilized the T'Loth class Cruisers during the attack on Ragesh III in 2258 because they knew the Centauri wouldn't counter their force with capital ships. The T'Loth is more like an assault ship. The Narn most likely kept a force of G'Quans in hyperspace in case they needed them. Furthermore, very little of the occupation of the planet was shown. We really don't know if there were or were not G'Quans involved in the attack.

[IPAndrews]

Well, I can see the T'Loth being better for boarding operations since it looks like it has a lot of room to carry troops and it has two fighterbays to launch boarding parties from.