He made his longtime friend and drinking buddy, Z-grade writer/director Edward D. Wood Jr. the executor of his estate. After his funeral, his wake was held at Wood's swimming pool, which each of the guests reminiscing about Duncan standing on the diving board.

[on often being cast as a "heavy"] I didn't mind being typecast as a badman. In fact, I enjoyed it. Me, Roy Barcroft, Jack Ingram, and all of us heavies worked all the time. We made good money because we would finish up a day's work on one set, walk right across the lot to another and get paid for two jobs in one day.