Irioincally, that *is* hisotorical accuracy, penal battalions were usually glorified infantry battalions with a large amount of men and really good equipment because they had to take the worst battles. I'll see if i can dig out the book i read about it.
I doubt that was case the through out the war.
The first penal battalion send to combat lost 2/3 of its strength in 3 days of attacks, so I doubt anyone would give the them best equipment and then sent them to die.