I coated mine in polyurethane and the paint when I first got the bike! Turns out this was a great decision. It slightly changed the hue of the paint work - but has protected it completely. Bike has done 10,000 miles on the road over the years.
Gary, wow - just found your post here. Did you ever part with this bike? I have an 1981 all original too. Same saddle, trim, etc as your picture. I was intrigued to see you say decals are available - do you have a source you can share?
Thanks!