Scott #99 With Guideline & Dot

I recently purchased this Scott #99. At first I thought I'd found a nice example that also has a hairline running vertically on the top border.
As it turns out it's not a hairline at all but a guideline and guide dot inside the "P", better explained in the link below from re-entries.com.

https://re-entries.com/quebecterc_5c.html

Are these common? Are they desirable? Any added value? Should it be mentioned in any future sale or just ignored?

Cheers, Bill

If selling in the future, I would say something like, "Copy clearly showing the guideline and dot-in-P found in some positions of this stamp." It may give your listing a second look and a better offer since it is so clear. Good luck.

I wouldn't call them uncommon. Here is a distinct horizontal dotted line. I have a used example too with similar markings. I believe what that article says about printing with dirty plates. There are a lot of scrappy things going on and this is just one corner!

To me, looks like ink pulls as most blue marks on G, E and 2nd line from the top seems similar to many admiral ink pulls. The dotted line at bottom of 1908 may be an unerased gideline, which is not uncommon on this series as well as 1897 Jubilees.

Whatever the case, you have a fine stamp there Hounddog.

Sorry for posting twice.

Really appreciate the replies everyone.
I had a choice between two different stamps both very very similar and I choose this one partly because I thought it had a hairline but I also really liked the corner perfs.
It's definitely going into my collection.
Again many thanks.

Cheers, Bill