Have you ever looked close at R2-D2 with Sensor scope the Stickers vary wildly. There are also single stickers and double stickers. 
Here are the different COO marks found on R2- Other variations can be found in the color of the Blue on dome, paint on legs, and he can also be found with a hard-torso- (hard plastic drum, a super rare variant. ) It appears the from is the same as the regular R2 since the dates are all 1977.
check out my guide on Figure variations for more info.
The Palitoy Empire Strikes Back – Star Wars Catalog With the exclusive Cardboard Death Star cardboard playset, as well as the unique Droid Factory and Cantina set.
The Droid Factory Playset came out in 1978 in a Star Wars box. It was also released later in a ESB box. The ESB box version is much harder to find.
For the most part all things are similar, although there a distinct variation in the base color can be found.
From researh it appears the Dark Brown base came to late in the ESB box, making the brown base much harder to find. The lighter color base has been found in both SW and ESB boxes.
Of course the coolest part of the Droid factory set is the 3 lever R2-D2. with its funky 3rd plug in leg.
Luke Bespin has an array of hair colors. and several head molds as well. – Here is a selection