The Aurora kit was first issued as a "Yak-25" and was one of Aurora's first eight kits brought out in 1953.
The model did not represent any existing Soviet aircraft. The design for the kit was taken from articles in aviation and popular science magazines and Jane's.
In 1954 Aurora changed the box art to "MiG-19". It was produced until 1970.
Above data from Thomas Graham's excellent book Aurora Model Kits, published b Kalmbach and currently out of print.
Graham's Remembering Revell Model Kits offers the information that their "Yak-25" was available from 1958-1961. It bore no resembelance to the Aurora kit in that it was a twin engine jet that did a pretty good job representing the actual Yak-25 in 1/50 scale.
These two books are superb additions to a modeling library and are actually pretty good reading as well as being great reference works.
Tom