Oops. I take back my original comment.
If you look through the entire PDF, you see LOTS of places where the scanning program chose to anti-alias something when similar sections and/or characters had not been.
Just go the the doc. You see it on lines, letters, and even parts of the signature.
I’m actually chalking this up to variations in the way the scanner took in and digitally processed the document.
That’s a fair observation. This could well be a scanning artefact, perhaps due to some kind of OCR intrusion.
But a scanner that OCR-ed just one number out of a line of equally-sized, equally-impressed numerals would be acting very strangely.
At the very least this scanned document contains a digital artifact which - perhaps innocently - mimics the effect of a crude forgery. For that reason it cannot be regarded as probative.
I would want to see a high resolution photo of the original B/C. The scanned image is simply no good. Trump, if you’re reading this, you know what to ask for!