I must admit to be baffled (more than normal) by the numbers. It is a known fact that Canada bought 127 Leopard 1A3s (C1) in 1978 yet the 1992 holding list only shows 114 with 77 being MBTs. So this leaves 13 accounted for yet by 1996 it is reported that the 114 C1s will be upgraded to C2.
Could there have been 13 parts and spares vehicles?
Leopard Holdings – 22 October, 1992
ECC 116101 Leopard C1 77
ECC 116102 Leopard C1 modified to accept Drivers Training Cab 37
Total Leopard C1 114
Here is a 1981 photo of a C1 with the Driver Training Cab.