No
Could be any of them as the "00" does not denote caliber, but the size of the shot contained in the shell.
the gun does'nt make a differance a 2013 mossberg 28gaand you're Ivery Johnson will shot the same loadjust get 28ga shells and you'll be fine.
none
Normally marked on the barrel.
yes
It refers to the size of the shot pellet. It is the largest size of "birdshot", and each pellet is about .190" (4.83mm) in diameter. There are about 62 of these pellets to one ounce.
That's a Mossberg 500 model
50-150 USD
In general Mossberg firearms are well made and dependable. They are not high $$$ guns, and do not have the collector appeal of other guns, but work well. Mossberg's motto has been "More gun for your money"
gun powder
It was made by Mossberg. They had an identical model 183t.