Colonel Klink gives a violin concerto and plays poorly. In real life, Werner Klemperer comes from a musical family and was actually a violin virtuoso.
All three of the main guest stars (Lee Bergere, Johnny Haymer, and Leslie Parrish) were in separate episodes of Star Trek (1966). Lee Bergere played Abraham Lincoln in The Savage Curtain (1969), Johnny Haymer played The Constable in All Our Yesterdays (1969), and Leslie Parrish played Lt. Carolyn Palamas in Who Mourns for Adonais? (1967).
This is the second time in the series that a brigadier general has dropped in and Hogan has to get him out.