Hopefully someone more familiar with this bit of 164 will be along shortly, but I have an early (pre-1993) model and it has separate front indicator lenses. I think 1993 was a change-over year, but sometime around then, they went over to a one-piece glass headlight -certainly a 1998 car should have had one and as far as I'm aware, the indicator was inside it with no separate lens of its own.
Can you post a photo of your car? as far as I know, there were only ever two sorts of headlamp fitted and it's very easy to spot the difference. The early one had a separate plastic indicator lens and the later one was a slimmer light (less tall) and was a one-piece affair.