The right way to tell is to inspect for the fig bud mite. They can be seen with a 60x hand lens like this one for $10 from Amazon:
There are visual symptoms that I associate with a FMV infection vs an active fig bud mite infestation. I don’t have good pictures of the symptoms on the smallest new leaves because I just knocked down an infestation and those leaves have fallen off or grown up. When fig bud mites are really bad the new leaves are stunted and discolored a reddish brown. In the pics that follow there are a few of those affected leaves that have expanded to small stunted status.
First symptoms I associate with recent fig bud mite activity. It shows as speckling or circular dots;
Now leaves with FMV symptoms: