yup, access is from the top. some on this forum have said that they can unscrew the canister by hand. i don't have that kind of grip, besides, on top of the canister, mine says to tighten to 28 NM.
the wrench looks like this - costs about $15 (steep but it'll last a lifetime). you may find an aftermarket one that fits but i didn't.
and BTW do a search on "topsider" & "oil change". even the manual indicates that oil is changed that way (via suction through dipstick).
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"