Try Cornell Publications. They have a few books on the company
There is very limited information on these revolvers, and the serial number you posted does not track with what information I have. The true serial number on many of these is stamped on the inside of the top of the frame, and the cylinder must be removed to read it.
It was made sometime between 1948 and 1952 - need letter code which is usually stamped on left side of receiver or left side of barrel, possibly under the wood/stock. It will be one of the letters: I ('48), J, K, L or M ('52), it may or may not have a serial number - but it will have a date code.
coin?
".410 or 12MM" and "One Piece Barrel" are marks used by Harrington and Richardson, 1877 to 1985. Diamond Arms was a trade name used by Shapleigh Hardware of St Louis. Your gun probably dates to sometime between the two World Wars.
These guns are typically very cheap. They range in price from about $50 -$100 usually going for around $70. There was a large influx of these guns from overseas around the 19th centruy. Typical gun makers are National Arms Co., F&W, Harrington/Richardson Arms Co. and Iver Johnson.
SASE (self addressed stamped envelope)
IF it HAS a serial number, it will be stamped on the receiver (frame) usually on the left side (as you are holding the shotgun). However, serial numbers were not required by law on shotguns and rifles until the 1968 Gun Control Act. Prior to that most low cost firearms were not sequentially numbered, due to the cost to the maker. It is not illegal to own a firearm without a serial number, but it IS illegal to remove a serial number, or possess a gun whose serial number has been removed.
I would like to get my passport stamped, please. The little skunk stamped his feet, so I ran!
Starting in 1965, the early models had grates with parallel bars above the burners, starting around 1968 they switched to a grate using round openings above the burners. The production date is generally stamped on the bottom of the case. For instance I have a 413G stamped 4-72.
Stamped is the correct spelling.
The company stamped the person as their best employee. This sentence uses the word stamped in it.
9 = 1959 G = Light Weight 71280 = Mfg # , starting with 1000