"Public Beta" didn't even come out until September 13th, 2000. No Beige machine ever shipped with OS X of any flavor. (The one possible grey area is that weird Rhapsody-based version of "OS X Server" that came out in March 1999; technically the Beige was discontinued a couple months earlier but it's "possible" that some dealers were preloading Server on leftover stock? Maybe? But yeah, no.)
I've never felt much love for any of the machines based on the chipset used in the Beige G3 that I've touched. (This includes the Beige itself, the tray loading iMacs, and the B&W. The Wallstreet/Lombard Powerbooks and early "Toilet Seat" iBooks are also based on the same tech.) They might be okay running OS 9, but with OS X they're all "finicky", and and the hardware itself seems unaccountably glitchy. (Really picky about RAM, PCI card incompatibilities, etc.) Even under the "classic" OS I'd swear the Beige is less reliable than a similar, say, 7600.