I asked my MX how hard it was to gap the new plugs, and he said confidently they come pregapped. I've never heard of that, but I have only worked on motorcycles. Seemed odd to me because Tempest doesn't know what engine they are going on.
I just installed 12 brand new UREM37BYs in an engine. I gapped them all. All of them were over .019".
Some engines call for a little larger plug gap, such as the O-235. If the plug manufacturers made all the plugs at .016", you'd have people breaking stuff trying to open the gaps.