I believe that only the one prototype was made. It would have been interesting to see how it would have worked out in a well-tested production weapon. Still, it looks like it was a precursor to the Stoner 63 modular weapons system.
As for the M-60, it's proof positive not to have weapons designed by a committee. Bolt lugs that needed the burrs stoned off every few thousand rounds, gas piston that could easily be installed backwards making it a single-shot, trigger mechanism that would fall off if the retaining spring wasn't properly set (and sometimes would anyway), riveted receiver rails that would crack and stretch, and no way to handle a hot barrel without an asbestos glove. Oh, and do NOT try to close the top cover with the bolt forward! and what genius decided the bipod should be permanently attached to the barrel?!?!
Still, it could have been worse. New ones usually operated reliably, and we learned to carry an extra bolt for when the lugs started to deform.
When it comes to reliability, though, the 'pig' didn't even come close to it's competitors; MG-3, PKM, or MAG-58.