Hi are the 1.0L & 1.3 L single point injection units for a mk2f the same. I have a 91 AAU 1.0l . If not would anyone know the different part numbers please so I know which one to look out for , Thank you.

you can look up the part numbers yourself on etka.cc

https://volkswagen.7zap.com/en/rdw/  Polo/Derby/Vento then select the year from the drop down list

From what I can see from the link above it has the same part no apart from last letter being an A for a 1.0L & a B for the 1.3L  so may be a slight difference somewhere.