Is This A Local Postal Precancel?

It has all the appearances of a local precancel, but I'm wondering why it would have been applied to a revenue stamp. The stamp is full gum never hinged, so obviously it was never used. A prank or experiment of some sort, or was there a legitimate application for such a cancel + stamp combination... a city entity perhaps?

Yes it is a local precancel - PSS type 841. When towns had precancel devices, collectors could 'walk in' with their own stamps to be precancelled, sometimes they brought their own ink and had a ball making denominations. Some postmasters were friendlier than others. About 5 years ago the USPS called in all the precancel devices and 'canceled' the program. Too bad - they were nice souveniers IMHO.
There are a few scattered towns that didn't get, or ignored the directive. There are a few intrepid collectors who still make them. It used to be much more popular.
They are collectable, not too common, but still inexpensive. Occasionally found on ebay like every other philatelic oddity.

Here are some other examples, the Cummington Mass might be a legitimately used stamp, the others not.

Thanks for the information. I guess they are more common than I thought. I tend to stick with 19th century only, so it looked odd to me.