They are not the SAME company, but yes Jayco does own the StarCraft company.
And while there are some exceptions, many of the models/floorplans are nearly identical. I have a starcraft 235fb and it is a twin to the Jayco 23rb.
And most of the comments here are equally applicable to StarCraft as to Jayco. The StarCraft Roll-Call is pretty much just that. Announcing to other StarCraft owners that you've joined the Jayco forum.
So welcome, fellow StarCraft owner. I hope you find the Jayco forum as helpful as I have over the past several years. I've been able to solve many problems and do many mods to my StarCraft by reading and discussing with these fine, upstanding Jayco folks!