Fyodor, you are almost right and this is absolutely correct about the first years of Regiment. But you've missed one important word - "low rank". Of course in Regiment's first years a lot of different NCO, soldiers and so on, were staffed mainly among nearby Finns. But all of the Officers of all ranks even in the first years were nearly almost Russian (by the Russian I mean not ethnicity, but citizenship). Later, starting from the second half of 19th century all the staff was consisted mainly almost entirely of Russians (Russians, Germans, Baltic Germans and other typical Imperial Russian ethnicities).
I've just looked through the list of all Regiments commanders during it's history and there are no Finns there;). Typical Imperial Guard's Regiment dislocated in Petersburg, but with Finnish name.