3a Cement Mixer

[Idris]

The NAMC’s “Catalog of all Series Matchbox Models” (second edition) lists variation code 3-1A (body type 1, 4-ribs barrel) as having unpainted MW. Is this an error piece or a genuine variation? Variation code 3-1B (body type 1, 4-ribs barrel, orange wheels) is noted as being light blue whereas all other variations are merely listed as being blue. Variation code 3-1G (matching Nick’s variation code 14) is noted as existing with either light or dark GPW.
Neither AIM's “1-75 Series Regular Wheels” catalogue (second printing, 1983) nor Stannard lists any variation not already catalogued by Nick. Neither does Houghton, whose variation table contains duplicate listings (entries 3a-1 and 3a-2).
U.K. Matchbox examined the model in vol. 2 no. 5 ((Jul. '78) p85 but did not list any new variations, but does note that shades of blue exist (c.f. NAMC variation code 3-1B described above).