In the case of ejection seats with 60 years of development I will firmly put my hand up and say YES.
In my mind every ejection seat that makes it into production aircraft MUST be right first time. Creationist? maybe. I'm also someone who worked on and around ejection seats for many years.
If it were right first time there wouldn't be any need for 16+ Mks of seat (from MB alone).
Everything can be improved, subject to experience and technology. The requirement will always be there, of course.