Does my key have a built in immobiliser

Hi I wonder if someone could be of help..
I own a very early 1992/3 Audi Cabriolet 2.3e which only has one key and would like to know if Audi 80s of that year had a built in immobiliser in the key..

The thing is my key on my 1994/5 A4 looks the same but (it's the key with the flashlight in the plastic casing) and has a built in immobiliser and my Fathers old 1994 A6 had a built in immobiliser to which was also the same looking key.

Its just that on my dash I can't see an immobiliser symbol and was hoping that I would be able to get away with just getting a new key cut which would save time and money..

The simplest way to check is to cover the plastic part of the key in tinfoil and try to start it.
I think it was an optional extra on your model.

Cheers size 12 the tin foil trick worked a treat..
I managed to get a new key made up no problem in the end and I didn't have to worry about any immobiliser issues