To explain further;
That little hump is your parking light on the 93-96 MKIVs. On 97-98 Supras they have incorporated that parking light into the signals. If you do the upgrade to the full 97/98 look (Headlights/Signals) with the MVP wiring kit its practically plug and play (minor splicing) and everything works 100%.
However if you're just doing the upgrade to the 97/98 headlights, what will happen is you're going to have an extra bulb/wire for the parking light that does not work with the 98 heads. So, just plug/wrap it (to keep from getting corroded or wrecked) and tuck away somewhere behind the headlights in case you wanted to go the 97/98 signal route in the future and then it will be available.
I would suggest getting the 97/98 signals as it is a much cleaner look, especially with the headlights.