I see only one reason it might not work: you will need pullup resistors on P0.
Note: if you had external code memory you could have a huge problem, just visualize
setb ... enable LCD write
code fetch(es) appear on P0.
clr ... disable LCD write

For the same reason, I suggest you do the following:
mov p0,LCDdata
push IE
clr EA
setb ... enable LCD write
clr ... disable LCD write
pop EA

Erik