no ;) (though you could start it there if you wanted, but.. why)

LD_PRELOAD simply loads a library of your choice that executes code in the process context, that's all. folks usually do this when they cannot recompile or change the running binary, which means they also hook and/or overwrite functions of the said program.

generally folks will have gvisor calls integrated to their sandbox code, before the target process starts, so no need for preloading anything in most cases