On Monday my play group is meeting to start the first adventure of our campaign set between Episode III and IV. In the first part of the adventure the players will ("might") come across a mechanic/junker who will be willing to trade the group a droid. I want to get away from the R2-D2 type Astromech droids. I have thought about using a BB unit but doing research tonight on the background of this droid-type it looks like it came into large use after ROTJ. Can you all help me think of a logical way to incorporate a BB unit into the time between Ep. III and IV? Thanks!

Early prototype that didn't go into production for years because Industrial Automaton was still sitting on billions of unsold R2 parts.

I know this reply is past your session, but the BB-series was based an evolution of ball-shaped droids introduced near the end of the GCW. Maybe it could be a "BA-series" prototype.

2 hours ago, A7T said:

"BA-series"

If you lock him in a shed full of junk, he can build a ramshackle armored vehicle in about half an hour.