Here is a true story of a strange one I had:

It was my 1st AR.
A Colt's CAR 15 "slabside" upper. I
bought NIB for $595.00 in 1980.
I think it was made in the late 70's
At the time, that was allot for an AR, but I bought it anyway!
The 'nam movies were just starting to come out, and I wanted a Forward
Assist because I thought it looked "cool", but couldn't find one.
I would haul that puppy strapped on the back of my '81 Honda 125 dirtbike
around in the desert, dust, cactus, and all sorts of thornbrush trees.
The CAR got all scratched-up, took a few "mishaps", along with me.
Once the bike fell right on it and bent the alum. buttstock,
which I hammered back so it looked kinda straight!
I kept it for 6yrs, continued to use and abuse it, but it never failed to
fire. It had a slabside lower on it as I recall.
In those days, John Q public thought all ARs were Machine Guns!
ARs were not very popular, and still had a "bad rap" because of the
junglejamming in Vietnam!
I 1986, traded the AR and the Honda 125 to a guy for a BMW R75S!
The BMW got stolen in the 2nd month, and I didn’t have insurance.
I got out of guns and motorcycles until 1991, when I got a letter from
the local FBI in Phoenix to the effect that they had my rifle, and
Would I please come to their office and pick up my property!
I freaked out!
I am not a criminal, and the worst crime I’ve ever committed is
speeding, so I asked my wife to come with me (for moral support) and
we got the AR back. It was like new! The Feds traced it back to the
original buyer, me, through records at the gunstore where I bought it.
As it turned out, the Feds said the AR had been sold and resold a few
times, and was found in the trunk of a car, along with several other
firearms and 8000 rounds of ammo, at the US/ Mexican boarder in Nogalas AZ,
headed Southbound and was in the possession of a Mexican National!
I asked why they wanted to give it back to me, and the agent in charge
said the investigation was over, and it was their job to locate some
kind of owner, otherwise it would be auctioned off. He assured me it
was Cool, and handed me the AR and said "Take it!"
So I did. I sold it and bought an old 1911 Colt .45acp. The next week.
I still have the 1911!

[b]So I did. I sold it and bought an old 1911 Colt[/b]

Gee, maybe you'll get it back again.

About 10 years ago I'm in a dealer's store and see this rifle with wooden furniture, thumb-hole stock.  Read the label and it is an ArmaLite AR-180(SCS) with a THREE DIGIT serial number.
Although a thumb-hole the rifle was still a pre-ban with flash-suppressor, bayonet lug etc.

Neither the dealer nor I had a clue as to what the rifle was worth so we finally decided that $900.00 was fair because it didn't have a folding stock, etc.

Anyway early last year I found out there were maybe (5) of these rifles in the country.

That AR-180(SCS) is now in ArmaLite's museum.