Yes.
It means you have a Mossberg Model 500a shotgun with the serial number L109563.
The best way to find the age of a Mossberg 500A Shotgun is simply to call the company's customer service line and have the serial number and model number handy. Mossberg has yet to publish a list of their serial numbers in relation to the dates of manufacture.
No
All.
If you have a 500, and it is a 12 gauge, it is a 500A. The "A" designates it as a 12ga. A 500B is a 16ga, a C is a 20ga, and an E is a .410.
The model 500 Mossberg is a particular style introduced in 1961 by O.F.Mossberg & Sons. It has undergone many style changes over the years, but 500A, B, C, or D are not style changes. A model 500A is the 12 gauge version of the model 500. 500B is 16 gauge. 500C is 20 gauge and 500D is .410 (which is actually a caliber rather than a gauge.
There is no difference. A 500 is a basic Mossy 500 receiver shotgun. Unless the gauge is stated, it's assumed it's a 12. The 500A is simply stating it as a "12 gauge" 500 in its name. The Mossy 500A is a 12 gauge model 500, the 500B is a 16 gauge model 500, the 500C is a 20 gauge etc. There was no 28 gauge so there is no 500D, contrary to many sources, so the next one was the .410 called the 500E. A 12 gauge model 500 and a 500A are the same gun.
It can be, if you are using a slug
You will have to call the company to find out.
175-350 USD
Depending on condition and variables such as ventilated rib or AccuChoke, from $100-$200. sales@countrygunsmith.net