A-bars for lights: When were they first fitted?

So I'm trying to be a bit different with my county 90, by keeping it as close to the original 1988 specs as possible rather than changing everything. However, at some point in the past it's had extra lights fitted- there are mounting holes drilled in the bumper and the (very dodgy, quickly removed) wiring for them was in place when I first got it.

When were these first available as a factory option? I quite like the look of the two extra headlights so if they were available in 1988 I might fit them. The earliest mention I've found so far is a 1990 brochure, with two round (7 inch) lights hanging below an A-bar.

According to the sales ticket for mine it left guthrie bros of montrose with an a bar and spot lights along with many other extras for a commercial tin top - such as heated rear screen , rear wiper , floor mats , mudflaps & grab handles in may 87.