Did these units ever see ditch lights or where they gone before they became a requirement?
No. The U36C's, and for that matter almost all of the CR U boats (there were some of the U23B's and C's that hung around for a while but never got them) were gone before ditch lights really started showing up in appriciable numbers. However, the C30-7A's (not the C30-7's) and the C36-7's got ditch lights, as well as the B23-7's and B36-7's.
Scooter