This was a somewhat common practice at the time since the cars did not change from year to year. VW and Mercedes made 'running' changes on the assembly line, so they did not get all hung up in model year changes.

So leftover cars were titled in the year they were sold, and the Germans (here in the US anyway) used Jan. 1st as the change date.

One reason for this was to prevent dicounting a car since it was last years model. Another reason was Mercedes were selling like crazy and if you did not like the way the dealer did business you were free to go buy somethng else.

I once bought a 1948 Chevy pickup at a police auction and the paperwork that came with it said it was a 1984. It took weeks to get this changed, and I remember the city clerk asking me if I was sure that I had not really bought a 1984. I told her there were more than a few differences between the 1948 and the 1984 truck and most of them were easy to spot.

When the city finally admitted it made a typo they told me to come up with the correct VIN.

It turns out in 1948 a car could be titled under the true VIN, the body style number or the invoice number from the factory. I had to get the state police involved to help me find the VIN which was not displayed anywhere. It turns out the plate had rusted away and the cops had to show me where the secret VIN number was.

Anyway, if a future buyer gives you a hard time about this you can always point out that things were just done differently back then. The last few numbers of your VIN are what really counts on your title.