Opinion: Possibly uncommon, never seen customs Pmks listed anywhere. All my examples (about 12) show violet ink, all smudged, indication high use of the cancellers, without ability to detect design of script.
Thank you again. Yes, I found many similar cancels in the internet that were smudged (but still it was clear that is was not a Gothic style). So this is a keeper for my (small) Canada section, as the cancel was applied with care, perhaps on an important document once.