Here's a tip since you own an '87 and may be dealing with other discontinued parts. Even though a part may be discontinued or obsolete, it can and in your case still does, show a part number at the dealership.
I was at my dealership today and yes, the part is obsolete but he was able to give me a part number of #71549-82A for your switch.
For me, having the part number has always helped me find obsolete or discontinued parts. I question why your dealership said no part number was available because you need to know the part number to know it is discontinued....