http://math.colorado.edu/~rmg/pint/
The number refers to the Weights & Measures Authority in the area where the glass was stamped/manufactured.
6 Birmingham
76 Manchester
116 Buckinghamshire
234 Lancashire
236 Gwent
303 West Yorkshire
366 Hereford & Worcestershire
371 Sandwell
414 Derbyshire
478 St Helens
562 Bury
883 West Sussex
1110 Kingston-on-Thames
1207 Sheffield
1535 Waltham Forest
1545 Warwickshire
I believe 2037 and 2043 are in a series allocated to ``trusted'' glass suppliers who are given their own numbers. The allocation can be found on an official web site. [Thanks to Steve Kelly for the address.]
STAMP IDENTIFICATION NUMBERS
DEPARTMENT OF TRADE AND INDUSTRY
WEIGHTS AND MEASURES (PRESCRIBED STAMP) REGULATIONS 1968
LIST OF IDENTIFICATION NUMBERS
National Weights and Measures Laboratory
Stanton Avenue
Teddington Middlesex
TW11 0JZ
INTRODUCTION
The following is a listing of the numbers allocated to local weights and measures authorities for identification purposes on items of weighing or measuring equipment. This list covers those numbers used to indicate equipment which has been passed fit for use for trade in accordance with the Weights and measures Act 1985.
Notes:
(a) Where a number has been cancelled, the name of the last weights and measures authority to which the number was allocated is shown in brackets.
(b) Numbers have not had static geographical locations; in the past numbers surplus to requirements in one area have been re-allocated to another part of the country.