"battalion flags" Now that IS a good one. In theory, they were issued to up to seven bats. per regiment. I do not recall the reg stating fanions were NOT to be issued to depot bats. It is NOT clear if these single colored flags (fanions) were ever issued en masse.
We can test this one. The 2e ligne had their's captured in Russia (1812) - of course, the depot bat was NOT present. Rigo, in his plate on the 2e, provides for one fannion for EACH bat of the regiment, including the depot.
One could also point out that those French units NOT allowed to carry eagles in the field, left them at the regimental depot. I guess the lads could have fun with these.
However, I digress, we were talking about Westphalian regiments.