You are fortunate that after so long a time frame that such an old paint job stands up so very well. My paint jobs from that long ago no longer satisfy me and I've even resorted to stripping old figures and starting over. They all look very impressive.
Thanks for the comment , I think the reason mainly stems from the change to using car mat undercoat sprays. Acrylic paint seems to really like that as a base and gives a lasting depth I also remembered to use a decent artist matt varnish around that time .However anything I painted before then, I am in the same boat as you lol