Typical location of frame number on nearside of headstock.

This location was used for all models from about 1954.

The frame number would consist of

• a year prefix (either a year eg., 54, or a letter prefix from 1958 beginning with 'A')
• model designation (K7, M25 etc.)
• serial number

eg. 57K7-0231 : 1957 K7 Captain

GM15-1315 : 1964 M15 Cadet