Yes, having a CTO seems to be required now with the FCT program and I can't think of anyone within in my scope of the ATC world in the last 5 - 7 years who has been hired by one of the "Big Three" (Serco, RVA and Midwest) FCT contract companies without a current CTO.
I think there may be places where you can still work as a "Range controller" with only RADAR experience and someone mentioned awhile back that Barking Sands over in HI was possibly going to have an opening, but I have no idea how accurate that info is as I did not come by it first hand. Still, if you have any interest at all, it might bear checking into.
Barking Sands used to be managed by a contract company, but not one you normally see in the FCT program...I think it might have been ITT, or another company like that, and they had a few smaller contracts with military bases. Anyway, If you make contact with someone there you might be able to find out more about your options in ATC with only RADAR qualifications. Good luck!