The most famous Fido...

I think a fido is a coin with error: a coin with a minting error

but also seems to be a Mid-20th century Acronym formed from freaks, irregulars, defects, and oddities, can anybody help with the date in which was first used?

any other meanings?

Acronym finder supplies a number of other uses, and verifies freaks, etc.:
[Dead link removed - ed]
I haven't found a date of first use yet.

A name for a dog of course. I do find "fido" the acronym in Webster's 1974 Collegiate Ed, which means it's been around for a good while. Coincidentally, I've experienced great difficulty in determining dates words first used; any followup on this very subject appreciated--DH

Dale, it seem to me that the people over at wordorigins on ezboard may be good at tracing dates. If the word is a 20th century US word newspaperarchives is good but it is difficult to use and requires a fee to get any useful accurate information

al, Thank you kindly, I will surely try the former (cuz free)

My 1948 'American Thesaurus of Slang' gives two definitions of 'fido. One is 'a trustee (prisoner) in a prison'. The other is 'fog intensive disposal of' - probably a WW2 acronym. No origin for the prisoner version.

Fido was the name of Abraham Lincoln's dog.