I’m not sure. I browsed around a bit and found a post where an epic staff person is saying only some of the decal blend modes work on mobile. so I guess you could make a few decals with different decal blend modes then package and see if any show up.
“Hi, because mobile uses a forward renderer instead of the deferred renderer we use on PC and console, we support only translucent, additive and modulated blend modes on mobile decals. For the same reason, only unlit decals are supported.”