Well, in essence, you wouldn't need to design for all 60 weapons individually.
You'd just have to design for one type of weapon and port that to all the others of a similar type.
Although I only used 1 sniper rifle in the Tabula rasa video, there were around 5-6 types.
But they were all of a uniform size, so it was only the meshes that changed.
So, you'd just have to code for Antiproton dual pistols, work out the mechanics of that, then port it to plasma dual pistols and so on, to choose an example.
And yes, in Tabula Rasa, it was only the active weapon you could see equipped at any given time, not the whole arsenal.
This was so you could see at a glance what weapon would be used when you hit draw weapon.