Most heraldic symbols do not have specific meanings in the general sense, although they may have when used for a specific family.
Historically Arms were usually granted to a specific named individual only, by the Crown.
The College of Arms, London, should have thousands of images beautifully drawn and coloured (The Lyon Office for Scotland), usually with a description of the Arms, for each specific family individual who was originally granted the Arms.
So they may introduce subtle changes, or redraw Arms, or recolour parts to denote a specific person.
Y-DNA unfortunately does not confirm which Son either, in the event there were several Sons.
Arms were usually different also to denote Cadency (Arms formally granted to younger Sons as Cadets).
It is not as easy as the original poster makes out.
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Today it looks like some might be able to buy a Grant
https://www.college-of-arms.gov.uk/services/granting-armsAs of 1 January 2020 the fees payable upon a personal grant of arms and crest are £6,600.
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However, it may be of interest to the family historian to get a firstborn Son (birth) continuous documented line backward to the individual who historically had the original formal Grant of Arms.
On my Male side since the 18th Century, all manner of 19th & 20th Century documents, numerous Certificates, numerous Registers, numerous Wills, Family Deeds, Family Papers, Deed Registrations, Newspapers, indicate we were
not descended from the firstborn Son on one occasion, either.
Mark
