No idea on the source for the name but to add to the confusion. Ten years ago or so, I had a one time chance to take a lot of air layers from Sunken Gardens for the Croton Society. The CaptGC growing in full sun was called 'Almost Edison' due to its resemblance to Thomas Edison, a well-known variety. Growing in shade was this big-leaved croton for which no one knew the name. Under better growing conditions, that 'Almost Edison' was identical to the previously mentioned big-leaved one with no name. I have no recollection when I first heard the name Capt Gilbert Cutler.
Now if you visit Sunken Gardens today, the same crotons are still there under the same respective conditions. If you look at one and then at the other, almost anyone will say that they are two different varieties. Yes, it's that big of a difference.
No idea when the Capt GC's were planted at Sunken Gardens, but judging from the size, I'd guesstimate 20++ years.