Yes But its Quite Tedious to do. its very possible.

basically you have to add the weapon as a custom hit box.
and have one weapon in both hands.

example when my character is facing right I want the sword in their right hand. so the sword in the right hand is set to custom 1
the sword in the left hand is set to custom 2

the above part is based on how you want it

the item you are looking for in the character editor. is "body part visibility changes"

this is an option for every animation

its also available in the move editor window

so you want to edit the body part visibility

so open chararacter editor.

go to where you input your idle animation

body visibility

open new

body part : Custom 1
visible : Check
trigger left : Check
trigger Right : Null
save as default : Check

open 3 more

body part : Custom 2
visible : Check
trigger left : null
trigger Right : Check
save as default : Check

body part : Custom 1
visible : null
trigger left : null
trigger Right : Check
save as default : Check

body part : Custom 2
visible : null
trigger left : Check
trigger Right : null
save as default : Check

now if you do this your character will properly only have the weapon on the side you want.  however this only pertains to the following animations

idle
walk forward and Backward (sometimes i dont know why)
any move file where you dont change state (jump or crouch)
and some gethit animations

so you have to fill in the crouching idle anim the same way as above
the jumping animation as well as a few others

its tedious. and has to be done FOR EVERY SINGLE CHARACTER WHO USES 1 HANDED WEAPONS

However if you do this properly with 1 character. then duplicate the character file to make a new character you will not have this problem as long as you set up the custom 1 and custom 2 animations to the prefab the same way on every character who needs it. at least that way it will save you from the tedious part later on