One method of identifying pressings is by a single-letter code printed on the center labels:
A = Sonic Recording Products, Inc. (until ca. 1975) or Goldisc Recording Products, Inc. (1975-1980s)
B = Electrosound Group Midwest, Inc.
C = Monarch Record Mfg. Co. (through 1984) or Electrosound Los Angeles (1985–1986)
R = RCA Records Pressing Plant, Indianapolis
W = Columbia Records Pressing Plant, Carrollton, GA
X = Columbia Records Pressing Plant, Pitman
Y = Columbia Records Pressing Plant, Terre Haute
Z = Columbia Records Pressing Plant, Santa Maria
A&M label history http://www.onamrecords.com/Labels_Sleeves.html
In Japan, the A&M Records imprint is managed by Universal Sigma and is independent of Interscope.
Some notable events over the years, courtesy of On A&M Records.com:
1967: Started distributing CTI Records in a deal that ran until 1970.
1967: The A&M Studios were installed in Hollywood, California. The label first appeared in the UK, distributed by Pye.
1969: A&M Records Ltd. opened in Great Britain.
1970: A&M Records Of Canada Limited was established.
1977: A&M opened an office in Europe. It was called A&M Records Europe S.A. and based in Paris. Titles were manufactured and distributed by CBS in Austria, Belgium, Denmark, Finland, France, West Germany, Greece, The Netherlands, Italy, Norway, Spain, Sweden and Switzerland.
1979: Started distributing I.R.S. Records. This deal continued until 1985.
1982: Started distributing the folk/new age label Windham Hill Records. This deal continued until 1989.
1987: Started distributing Twin Tone Records (selected titles) and Nimbus Records.
1988: Launched sub-label Vendetta Records in NYC. It was shut down in 1990.
1989: A&M was sold to PolyGram, but operated under Alpert and Moss's leadership until 1993. The sale included A&M of Canada and Britain and was effective January 1, 1990.
1991: Agreement signed with Jimmy Jam & Terry Lewis to launch Perspective Records. It was shut down in 1996.
1993: Unhappy with the increased integration of the label into the PolyGram corporate structure, Alpert & Moss left A&M and start a new label, Almo Sounds.
1995: Three year agreement signed with producer Ric Wake to form DV8 Records.
1999: PolyGram becomes part of the international Universal Music Group.
1999: A&M is made part of the Interscope Records/Geffen Records/A&M Division of Universal.
2004: Universal Sigma begins using the A&M Records imprint for domestic Japanese releases (operating independently of Interscope/Geffen/A&M).
2006: A&M Records is made a frontline label in the UK
2007: Universal merges A&M with Octone Records and places Octone's management in charge of combined label (except in Japan and the UK)
Labelcode: LC 0485 / LC 00485