Ah! I’m kinda late to this thread but hopefully I can help?
There are three types of serama in the US. American, Traditional, and Malaysian (also known as Ayam or Extreme).
There are two ways to show, in-cage, and table top.
In cage showing is done by the ABA or APA. Only American seramas can be shown. There are currently three recognized colors, white, black, and exchequer.
Table top is done by two breed clubs, SCNA and Serama USA.
SCNA recognizes traditional and Malaysian. The birds are scored on type only. Most table top shows are SCNA.
Serama USA is strictly Malaysian. They are scored on type. However there are preferred color varieties in the standard. Their standard is somewhat different from the one SCNA uses.
The standard for traditional and American is the same, one is just recognized by the apa based on pure colors. All American birds are traditional but not all traditional are American.
SCNA shows and APA shows are often held in the same place and packaged as one show, but to sign up there are two different entry forms. Make sure if you want to do table top you actually sign up for table top. I don’t know if you can do both with the same bird.