That is not exactly what "abjab", when the word is used alone, means AFAIK. Abjab is a type of writing system in which (in contrast to true alphabets) each symbol or glyph stands for a consonant, in effect leaving it to readers to infer or otherwise supply an appropriate vowel.
However there is a system known as "Abjab
Numerals" that assigns numbers to each of the 28 letters of the Arabic alphabet. I realize this is undoubtably what you meant, but i wanted to point out the subtle differences so that nobody was confused.
Abjab Numerals is very similar in many ways to Hebrew Gematria. A similar thing was also done with the Greek alphabet.
I know more about Gematria then these other systems. In Gematria it is possible to find inner knowledge through words that add up to the same numerical value. I suspect a similar concept applies to Abjab Numerals.
While i can see why you felt this might be best as a separate thread from the sword you link to it might be best to upload some blade examples to this thread so that this is not seen as a Miscellaneous Subject thread and moved to a different page.
https://en.wikipedia.org/wiki/Abjad_numerals