I guess I like a challenge.
I spent a few minutes searching, and found this listing on ebay, but it is pricey at $120...and it does not reveal what original vehicle it was used for.
HOLIDAY RAMBLER ALUMI LITE 1987 1988 1989 LEFT HEADLIGHT SIGNAL LAMPS LIGHT RV | eBay
There's another thread here on IRV2 about headlights on your model, and it lists a number SAE-H-86ET 23V7H. I could not find a cross reference to an original vehicle. The other thread is at:
. This thread mentions "Pre '91 escorts"
Looking in ebay, I searched for 1990 ford escort headlight, and found multiples that look like yours for 1985 - 1990 ford escort.
I hope this helps.