Mills MRA two types of different brand ?

Vishay bought Mills in 2011 and they have been making them ever since, in brown. There were four, color/finish versions of the older, made in the USA, Mills wire wounds: Dull(flat) in either black or brown / shiny and smooth in either black or brown.

Some vendors still have a supply of NOS, USA made Mills resistors.  Vishay bought the company, in 2011, and moved production to Mexico.