I did a quick google image search and they appear to be ordinary raised rectangular units, commonly available at auto and trailer parts stores and online. I see no reason to match the originals. Biggest favor you could do yourself is replace with
LED lights. Go for the largest (most LEDs) you can find for safety.
BTW- the thread
title reads like you’re looking for a trailer. My curiosity was piqued because it’s unusual for someone to want a specific model year of a vintage trailer.
PS- saw your other ad on another site. The curved shell means the
lights are mounted closer to the center where the curve is less. As far as I know, no special spacers are used, just standard surface-mount RV
lights, and yes, they are not perfectly perpendicular to the centerline. A few manufacturers use custom fairings or recesses. Perris did not. My
Scamp is the same.