Not without completely rewriting the input file element. I would not suggest that though. Besides, I would expect most people will expect it on the right, so they would be confused.
Suggest the client view the site using Safari for the Mac. It has the file select button on the left.
It's up to each browser and each operating system to render them as they choose. There is a good article covering this (which screen shots showing the browser differences) at the following:
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.