Yes. Just because something is necessary for the brain to operate doesn't mean specific versions need to be preserved rather than some generic version. It is necessary for you to have a skull to think and live, but I don't think many people expect the individual bumps and indentations to need to be preserved for a faithful upload...
On the other hand, people probably have slightly different versions of glial cells, and which model of glial cells you have might have some effect on your personality and intelligence.
Actually, it's probably not just one model per person. I've been told that there's more than one sort of ATP (copying errors and variations), even inside one person, and if ATP isn't universally identical, then you can't expect anything else to be.
I know next to nothing of biology, but I would naïvely expect the structure of the ATP, ADP, AMP, etc. to be fixed across all organisms with mitochondria. Shouldn't copying errors or variations that produce something other than ATP in place of ATP kill any eukaryote, let alone a human? Perhaps you mean variations to ATP synthase?
The WP article doesn't mention anything of the kind, and when I studied freshman biochemistry nothing like that was mentioned, either. OTOH there's a lot of variations in the (vastly bigger, more complex and more diverse and numerous) organic molecules that work with ATP.
http://www.scientificamerican.com/article.cfm?id=marijuana-reveals-memory-mechanism
I wonder what the implications are for brain preservation and whole brain emulation? If glial cells are important, then saving and emulating the neurons alone probably won't be enough.