The Dizzy for a GU code motor when fitted to a Syncro can be either from Bosch, Ducellier or Valeo as they appear to have fitted whichever they had in their hand at the time!
More confusingly VW use the same part nr (026 905 205AC) for all 3 of the dizzys from the different manufacturers even though the dizzy caps & rotor arms are different!
Here are the three manufacturers codes for their dizzys and the correct VW part nr for the Dizzy cap & rotor arm.
Manufacturer —- Mfr P/N
VW P/N Dizzy cap – VW P/N Rotor arm
Dizzy 1) —- Bosch
026 905 206F
027 905 207
055 905 225B –
Dizzy 1A) — Ducellier —- 026 905 206AC — 026 905 207A —- 026 905 225K
Dizzy 1AB) – Bosch
026 905 205AC — 027 905 207A —- 055 905 225B
Dizzy 1AC) – Valeo
050 905 205AJ —- 026 905 207A —- 026 905 225K
As well as the above differences the Dizzys also have different vacuum advance units, hall sender units, impulse rotors & internal dust covers.