Army Building Question, CCWs

Greetings All, 

When purchasing upgrades for units, is there any distinction between CCW(A1) and CCW(A2)?
In examples I'll leave out a lot of options for brevity. 

For example, in the Human Defence Force;
Each model starts with an Assault Rifle and CCW(A1)
One model can switch that for a Pistol and CCW(2)
He can also switch a CCW for an Energy Sword (A2, AP2).
Is there any benefit for taking the pistol, if I also take the energy sword?

Similarly, this time in Hive Gangs (so technically Skirmish);
A model starts with a Pistol and CCW(A2)
They can replace their CCW(A2) with another pistol and a CCW(A1).
They can also switch a CCW for an Energy Sword (A2, AP2). If I want to do that, is there anything stopping me from getting a free pistol first?

Thanks for any advice.