Do I Have The Find Of A Century Or Is This A Common Dud?

I bought a stamp album on line. As I was enjoying my new collection of stamps, I came across a potential jack pot. In the album, it was under the place holder for Scott 321. This particular stamp is worth thousands, but I don't think I got the real deal, but there are some characteristics that sort of support the big find.
Here is a picture:




Clearly, it is not an imperf so that rules out 320 and 320A.
It is not perfed all around so that rules out 319 and 319F, Types 1 and 2.
However it does have 12 Horizontal Perforation which means it could be 321 or 322 depending on the type which I have not analyzed.
It does have Watermark 191.

Could this be an imperf where the horizontal perforations were added after purchase?
Is there something I am missing here?

Look carefully on the left side. There is evidence of perforations that were almost trimmed off. Value is minimal.

Vertical perfs visible on the left side...NOT a 321, a trimmed 319.

Excellent eye Partime. I completely overlooked that. Looks like someone was trying to cash in on the big payday.

Or just fill the album space the easy way Joannehasstamps.

A strange hobby when a few tiny indentations on the edge of some paper means six figures.

When one understands the back stories of various items it becomes less strange.

I would like to know how much the previous owner paid for the stamp.

Copies with a little larger margins go for $20-40 on ebay. What is basically happening is booklet singles are being destroyed to create these space fillers.

If we look back to the early 20th century, Coils were not considered a separate issue, and thus were not carefully saved except by a few collectors.

Travel up in time to today: Scott is making separate entries for modern stamps issued in sheet form and booklet form. At some point, that review is going to be retroactive. And folks are going to discover that those old booklet singles have largely been destroyed.

To add to what alub mentioned, the booklet stamps have one major strike against them. Back in the day when sheet stamps were printed then would be cut into smaller panes for sale over the postal counters. Those smaller panes that had one or two edges which were cut and the so-called straight edge stamps which collectors generally avoided to chase the fully, four side, perforated stamps. Now back to booklet panes, with only some rare and expensive examples (AEF booklets), all stamps from a normal booklet pane had one or two straight edges. Those stamps were therefore avoided. Full booklet panes and booklets were saved, but not the individual stamps. Even when on cover the straight edged stamps were avoided, sheet or booklet.

I posted an item today which only likely exists in its present condition due to having a JQ5 with a straight edge. See:https://goscf.com/t/83137 12th post down. The item was torn for the stamps not as postal history. If intact, it would be a four figure item.