I don’t think so.
Here is a model of a simple sphere I created, unwrapped, and textured in Blender. It has 8 separate UV islands and all mesh edges are welded.
Exported from Blender as obj and imported to Rhino. It looks correct when I run _UVEditor:
Also looks correct in rendered view:
12x12_uvsphere.3dm (3.2 MB)
All looks good when I run _Check on this mesh - valid closed mesh with no naked edges.
I can produce the same results UV unwrapping in ZBrush and 3DCoat as well.
-Kevin