On my ’86 Vanagon syncro, 7 passenger, there are two m-code plaques, a white paper one below fuse box and a metal one under driver’s seat.
First the vin can be decoded (link for site with vin decoder)
My vin decodes as:
made in West Germany, by VW, multipurpose van, 1980-1991 bus, 4-cyl gasoline water cooled, passive seat belts, vanagon, a check digit, model year (G=1986), Assembly plant Graz Austria (bodies sent to Graz from Hannover for syncro mods), then lastly production number.
So far what i have decoded from white plaque/sticker:
255 = Caravelle, Vanagon, Westfalia etc; LHD.
4C7 = not found on any list so far.
AAN = not found on any list so far.
LH8U = paint code, Bronze Beige Metallic.
D24 = not found on any list so far.
D26 = not found on any list so far.
D30 = not found on any list so far.
573 = klimaanlage (+leuchtspiegel in beifahrersonnenblende M 999), overhead air conditioning.
758 = “Sonderausfuhrung” Steuerungsnummer fur Programm Steuerungs-Zwecke von Internen Sonderfahrzeugen. Internal control number for special vehicles, I assume its a tag for syncro production. “Sonderausfuhrung” means special model, note there should be umluat on middle “U”.
975 = Zusatzheizung (Webasto BBW 46.10, speist in den Wasserkreislauf ein, keine standheizung (+ batterie 63 Ah M 597). aux heater (coolant type), Webasto plus 63 Ah battery.
And on the metal plaque below driver’s seat:
40 = could be produced 40th week of the year. Door jamb sticker says 10/85, so its close. But syncro production is complicated by the shipping of bodies from Hannover to Graz.
7 = ?
KN = ?
2554 = is it the model number? 255 = Caravelle, Vanagon, Westfalia etc; LHD. Not sure about this.
C7 = ?
X4X4UR = another code for the paint, Bronze Beige Metallic.
113 = Canada version.
526 = Luxury edition Caravelle (ha!).
66 = ? if it was an m code it would have a leading zero.
025 = Instruments with trip counter and clock.
557 = not found yet.