I don't think these ever got a specific canon designation, but it was a design change made for orbit to surface infantry deployment. Bigger doors for pressurization of the cabin, spotlights instead of ball turrets, anti-pursuit lasers etc.
Although it doesn't have its flank guns, I think the closest archetype to base it on would be the Hound's Tooth. The ARC-170 already covers off on the double arced platform, so it makes sense in terms of gameplay to make it a little different and maybe give it a 180 arc anyway. They are about as long as the Scimitar apparently so large base makes sense scale wise, but a large based missile platform sounds really lack-lustre. They'll need to do something unique with it for it to stand out at all.
2 Missile slots, a gunner, a crew, reinforce and reload actions, a red stop etc. maybe a 8/3 hull and shield split? I think it should be more tanky than an ARC, especially if its a large base. It shouldn't be expensive either though, so maybe 2 attack dice primary to balance the cost? Then it can give the missiles something to do.