To my knowledge, there was never a CRT extension for Links courses for the PC. I'm not sure about the Mac, but it doesn't seem so, as Jim pointed out. Is there a chance these courses could be for Tiger Woods golf or some other golf game? What are the course names (this could tell us if they were from another game)?
The old Access courses that were DOS based had a CRS extension and had to be converted to CRH when Links 386Pro came out (I believe). The CRH could then be converted to CRX using Links LS (1997). When the APCD came along, the courses were changed to CRZ. The converter can be downloaded from
http://www.linkscountryclub.com or can be found on CD3 (or was it CD4?) of Links 2003.
Armand