if you missed it - "serial and engine numbers"

[Been Here Before]

Beginning December 12, 1925, engine serial numbers were also (usually) stamped on the frame. Obviously, those were matching numbers. Today, often they're not because the engine is a replacement.

According to the FHA site by 1924 there were over 15 million automobiles registered for road use.
https://www.fhwa.dot.gov/ohim/summary95/mv200.pdf

By this time, late 1920s, automobile thefts and chop sites for parts were well established, both manufactures, insurance companies, and law enforcement were looking for a way to track possible stolen or miss used vehicles...having both similar manufacturing numbers on motor and frame/body numbers helped with the tracking.

Remember that once, one of the ways to once date a Model T was the engine number only.
Another Ford Birthday Party, Telling When Each Ford Was Born and Bring Motor Numbers Up to Date, The Fordowner, June 1919, PP63-68.

Too, Motor Age, February 1922, carried an article, Manufacturers will aid Theft Protection, that stated "The first step which the automobile thief usually takes in changing the identification of stolen automobiles is to change the engine numbers so that the automobile engine can not be identified." From that introduction pages 63 to 71 list all know sequences of vehicle identification numbers from ACE to Winther, circa 1911 to 1920. Of interest the Ford is identified from 11-1-1912 serial number beginning with 15001. With the article are diagrams showing the location "serial and engine numbers".