I have a number of TV and movie cels.  
First of all, the movie cels are larger.
They didn't use regular TV sized cels. 

As for cels of Kenshin and the crew, the same
studio that did the TV series did the movie so
it's hard to accuse the movie of being 
inconsistent.

Movies have higher budgets so the cels usually 
have a lot more details than the TV, but for RK
that's really hard to say, as the TV animation
was very well done.  


I've posted a pic of one of my 2 kenshin movie 
cels.

I hope this helps you ID your cel...