Masterwks, You can still find it but it's hard to good deals on it.
12 and 20 come is those 100 round sleeves from most makers,Remington,Federal,Winchester. I haven't been able to find those for the 16.
Nor is the availability of different loads and shot sizes. Most brands just have the basics, 5-6-71/2-8 shot.
The Sweet 16's are great guns - classics. We had one in the family and a Butt-head cousin ended up with it. I got an older Remington 870 Wingmaster 16 w/ polychoke.
Another cousin got a LC Smith double in 16, all from the same grandfather. He loved the 16 gauge - he felt it was the best of all worlds. Some of the shots I saw him make with those were amazing.
I would hang onto that one, they are sought after very hard.
I still have a Browning A5 Light-12 that I hunt with, would love for it to be Sweet 16.