Today, there's a very good chance he would be signed. Back then, the UFC normally signed guys at a higher level that hadn't proved they don't have the potential to become champion yet. Manhoef had shown he wasn't ever going to be a serious top fighter, that he was never even going to be a full time MMA fighter (part time MMA, part time kickboxer), and was just a fun fighter; UFC generally didn't sign guys like that.
For example, it used to a known rule that anyone who lost 3 consecutive fights would be cut. It didn't matter who you were. You could be Matt Hughes, Anderson Silva, or Conor McGregor. If you lost 3 fights in a row, you were gone. There are several guys I can think of on 4-5 fight skids right now that weren't cut. Carlos Condit comes to mind real quick.
As the UFC has become larger, it's also expanded the scope of fighters it puts and keeps on the roster.