Just saying.
The SIK with Redboard was my first step into the Arduino world, now 3 years ago.
It’s not gone:
The Redboard Kit is also still on the Sparkfun web site.
https://www.sparkfun.com/products/14265
I have seen and bought earlier revision kits on All Electronics.
Hmm
I was sure that it stated ‘discontinued’ somewhere for the board. Glad it’s back 
There are older revisions of the Redboard that have been discontinued.
https://www.sparkfun.com/products/retired/12757
https://www.sparkfun.com/products/retired/11575
https://www.sparkfun.com/products/retired/12788
https://www.sparkfun.com/products/retired/10908
That’s probably what you saw.
I know that an older revision of the Redboard and the SIK with the older revision Redboard. Can be purchased on a surplus electronic equipment and component web site.
So it looks like retired revisions where sold to the surplus electronics company.