Dave said:  Volkswagen considers anything built 01/SEP and on the next
model year.  So your 09/89 would be classified as a 1990.....
Actually, it's not VW, it's the 'tradition' created by the US
manufacturers in the '50's and '60's.  The plants shut down in the
spring to re-tool, last cars of the 'model year' came off the line in
April or May, and the first of the "New Model Year" usually shipped in
September.  Ecause of this, even though manufactured in one calendar
year, most states register anything sold new after 15 Sept as the next
model year.  My '85 Westy had a body manufactured in 12/84, and my '90
in 11/89.
BTW, the '90 originally had the 'touch me and I will crumble' fiberglass
bumpers, as opposed to the 'touch me and I will wrinkle' metal bumpers.
I replaced them with the Volkscafe bumpers, now 'touch me if you dare'.