The Peterson Javelin was built mostly out of metal and domed rivets.
The company carried out tests on the rivet shapes and reckoned there
was no difference between flush and domed. Furthemore they obtained
thier own 'cheap' rivets which they had FAI approved which saved them
a fortune.

The report can be found on the SSA website under the articles on
flight tests of various gliders.

Of course this relates to the 'then' technology, 'now' may be
completely different