After choosing the second specialization, you cannot disassemble the equipment that was saved in the template for the first specialization. To remove this equipment you have to go to the camp, change specialization, save it with new equipment. Only after that you can delete unnecessary.
I found that you can, But you have to go into a bivouac to do it.
In the Bivi, under preparations, select you chosen class and then in the top right under gearscore is a "Edit preset" click it and then change the gearset to your current equipped items, the low lvl items you want rid off that were previously locked in the preset are now unlocked.