can an inmate in a prison get conjugal visits if have prior offenses

Family visits (which include conjugal visits in a private trailer on the prison campus) are allowed within the discretion of the facility. The correctional counselor to whom the inmate is assigned is the place to start the application process. California Department of Corrections and Rehabilitation regs. 54020.33, et seq list the rules.

Here is a URL which gives you the text of the related rules:
http://www.cdcr.ca.gov/Regulations/Adult_Operations/docs/DOM/NCDOM/2007NCDOM/07-11/DOM%20Text%20-%20RDP.pdf