the C5 has been out undercover for some years now being stress tested, so I've read on this forum, so I would think the r&d was done well before it entered service for testing. all this, while times were good in the industry.
the S*** hit the fan out here last year and the c5 was officially launched approximately one year later.

so no, I don't think pay cuts financed the c5s' r&d. But I would bet they are financing other things with the pay cut the crown guys took.