It's most likely been run on very short trips with naff oil and never really got hot enough, new stat is a good idea, I wouldn't be taking the head of based on this, I'd put some wynns engine flush through for 200 miles first, not the 10 minutes idling like wynns say, I always do this prior to every oil change, my cossie is on 180,000+ miles on bottom end, ace compression performance, but oil rings starting to go now.
tabetha