Yup - you have it all correct.
The Crosman model 1100 - patterned after the Remington 1100. The shot shells were available in three different shot sizes - #8, #6, and #4. The shot shells were colour coded red, yellow and green for the different shot sizes. You could also get a thrower to launch a two piece, bright yellow, plastic skeet bird into the air. When hit, the outer ring of the bird would separate, indicating a hit. The bird could then be snapped back together for re-use. A bit more rare, but Crosman also made some miniature clay birds for these as well. These were very fragile, and had a very low survival rate, so they are not often seen nowadays.
These shotties can also fire a .375" lead ball at speeds just under 500 FPS.
They can still be found on the used market, in the $300 range.
I have a very nice boxed specimen of a Crosman 1100 in my collection, along with specimens of the ammo and both types of trap birds. Sadly, I haven't managed to find a thrower - yet - lol.