The KV-2s are about the only ones I don't have of the Trumpeter KV variants so I can't tell you how it looks. However, Neil makes no mention of the welds needing any changes in his review on 4BOgreen:
I'm therefore inclined to believe that the kit welds are fine. The site is a very useful resource for the KV series by the way, in case you were unaware of it.
There's nothing cushy about life in the Women's Auxiliary Balloon Corps