No. That went out with the ark.
Pretty sure it's only boxing now where if you turn pro you can't compete. All the track and field stars are paid, same with the golf, football, handball (in Qatars case), tennis, rowing (GB's case), pretty much all of them.
Pro boxers are allowed to take part in the Olympics now. The ruling was only made a couple of months ago so only a few have taken up the option for Rio. I suspect the next Olympics will be dominated by the pro boxers unfortunately.