Sorry -- finger fumble...
SVR4 (aka UnixWare) was available for source - the problem is many people did like the price to see it. It was $100K. But the source was available it was open and many, many of people with PC and had access to it, wrote drivers for it etc. There were books published about it. It was hardly secret.
That said, BSDi was $1K until the law suite and the pretty reasonable at the time, and NET2 would eventually become free in the same way as Linux - purely a copying fee.
Linus has gone on record if he had know about the 386BSD download, he would have used it. It was a case of not knowing. But as Larry points out, some people still are not happy with the results. It's also not clear that people like me would still not gotten scared when the court case came -- which clouded things...
I'm not sating Linux was (and is not) important.
Just saying please don't say UNIX was not Open. It was. Unix was not Free.