"...also the date code (the earliest I found is 6512) was only used by EMI"
I have differently formatted date codes on two early 80s Motown LPs distributed by RCA UK; "So Right" by High Inergy (STML 12170) shows RWG582RS (May 1982, I take RS to be Robert Stace, but I don't know what RWG means) and "Back to Basics" by The Temptations (STML 12196) TM 10/83 EUR (October 1983, both cover and record were made in West Germany, presaging RCA's centralization of all European vinyl production in Germany in the following year).
And sorry to be pedantic, YankeeDisc, but please please, do NOT include a hyphen in Tamla Motown, this is one of my biggest bugbears. Occasionally US Motown might have informally used Tamla-Motown or Tamla/Motown as business names in their ads in Billboard, Cashbox, etc, but the international label brand name has never had a hyphen.
The stamped mono cover on mine has MAL 762 on it's spine, as was to be expected. This is not the first occasion of the "Stereo stamp" I have encountered on Pye product. Later on they went for stickers it seems.
As for G&L, I believe it was EMI policy to have them include both mono and stereo cat#s on the flip part, also the date code (the earliest I found is 6512) was only used by EMI. Interestingly, I did not find printers named on releases from Philips/Fontana and related labels (just a quick check on a few of my records, not really proving anything). Instead they have a copyright claim and refer one to Phonographic Performance Ltd. of Oxford Street. to obtain a licence to play records in public.......
I do so remember seeing this album, as I trawled through record store bins/racks in search of bargains in the late 60s onwards.....never bought one though, not my scene, guv.
The sleeve printed and made by Garrod & Lofthouse Ltd is their classic flip back, with two components, the laminated front with "three flipback ears" usually litho colour, and the monochrome separate back sheet.
To save money I guess, only one front sheet is printed, and as we have both mono/stereo versions posted, no signs of differentiation, and the back sleeve ditto, just the red ink stamp with the MALS prefix. I wonder who got that scintillating job.....
G&L also printed for EMI, so if you check out Tamla-Motown early issues, the front and back sheets of their albums, from start date March 1965 usually had totally separate printed components for a mono TML prefix, and a stereo STML prefix album sleeve.
As time progressed, the Tamla-Motown laminated album front sheets dropped mono/stereo, and just the rear monchrome sheet had the full catalogue number, mono or stereo.
Sooner or later mono TML albums were dropped, and only stereo STML issues continued.
Of interest is the "spine" album info, which we do not really acknowledge on this website, but normally included the artist name, album title and catalogue number, so this Marble Arch album may have shown MALS 762 on the spine edge, and the mono version MAL 762......any owner to confirm, please....