ACW or Blue and Grey?

I spent some time over he weekend completing my first pair of block armies. Each army consists of 48 blocks and their composition is similar as follows:

18 x Infantry
6 x Cavalry
6 x Artillery
6 x Command
6 x Infantry skirmisher/dismounted cavalry
6 x Cavalry skirmisher.

The blocks are blue and grey and as such will be used for the land element of my ACW river based activities but going forward could easily be used for other armies or periods. Which leads to a further consideration - that of unit identification.

Originally I planned to have a label mounted on the rear face of each block giving the unit/commander identity which would also help to add a little period specific personality to the army being used. Now I am not so sure as should I adopt this approach then it means collecting, for example, several armies of blue blocks should I want to game using a blue army from different periods. This seems to defeat the object of using generic troop blocks so I will need to think of another idea for identifying the component parts of the armies being used.

One idea that occurred to me was to use magnetic strip. By place some metal paper along the rear face I could merely produce labels of unit names for whatever period under consideration, mount these on magnetic strip and affix to the block as and when necessary.

Alternatively I could just add a generic label e.g. Infantry 1, cavalry 3, artillery 4 etc and record the historical unit equivalents on a roster sheet e.g. Infantry 1 equals 20th Maine and so on.

I will give this some further thought and in the meantime will press on with the blocks for the Balkan Wars.