1993 Tandem Trailer- Drum brake size?

[scustoms]

1993 Tandem Trailer (PS205 if it matters)

I had a brake dragging last season before I put the boat away for the winter.

I was looking here

The brakes haven't been touched since new (boat was stored 2 miles from the lake) before I bought it. I am leaning towards all new backing plates but was looking at the price prior to tearing it apart.

Are they 10" or 12"?