I posted a brief version of this to Weber Nation a while back, and the link might be buried in a thread here somewhere, but it deserves a thread of it's own. We've seen a few of these very early "custom" Weber kettles over the years, the unique finish is well...unique.
Some call it "spiderweb", or "splatter". Most of them appear to be black kettles with white or greenish-yellow squiggles, but they made other color combinations. So what inspired them to do this? Was it Jackson Pollack - who died the year this finish was introduced? Was the Custom an homage to his contribution to the art world? Unconfirmed sources provided proof that Mr. Pollack was an early Weber kettle fan, and was inspired to apply his talent to at least a couple grills:
A more believable answer may come from the Brush-McCoy Pottery Co. From 1911 to 1925, Brush-McCoy made some very unique pottery, but mixed in with the usual colors and shapes was a finish they called "Chromoveil". Perhaps George Stephens and his wife were pottery collectors?
Fast forward to 1956, when Weber introduced their own version of this finish with the "Custom". Both 18.5" and 22.5" kettles carried this unique look for a short time. Every one is different. I can only imagine the person who was charged with applying the "veil" to these kettles. As luck would have it, one of the vintage photographs at the Weber Grill restaurant in Chicago (on State Street) shows Weber sales guy Bob Krug introducing this unique kettle at a live cooking event.
The inscription refers to the finish as "Chromavale", but I suspect that was a simple misinterpretation of a unique word. It's the 60th anniversary of the Custom this year. I say they make up a few to celebrate the occasion!