CLAYTON, Mo. — Rock star Axl Rose was found guilty yesterday of property damage and assault during an aborted Guns N’ Roses concert last year that escalated into a riot.Rose, who was not required to be present for the proceeding, was given two years’ probation and ordered to pay $ 50,000 in donations to five local social service orgs. St. Louis County Associate Circuit Judge Ellis Gregory accepted an agreement reached by attorneys from both sides of the case in issuing his order yesterday. Attorneys had agreed to let the judge rule on the evidence–police reports and videotape from the riot–and avoid a jury trial. Rose had pleaded innocent to four misdemeanor counts of assault and one count of property damage stemming from the riot that broke out during his July 2, 1991 , concert at the Riverport Amphitheatre in Maryland Heights, 15 miles northwest of St. Louis. Several thousand dollars worth of property damage was reported by the outdoor theater. Gregory said he found that Rose was guilty of the charges “beyond a reasonable doubt.” The judge said the two years’ probation would be monitored by officials in California and would be subject to special conditions. The conditions allow Rose to travel in connection with his work. Gregory also amended the probation regulations to allow Rose to associate with known felons within his band. Prosecutors have said two members of the band have been convicted of felonies. The judge noted, however, that he wanted such associations confined to that narrow circle.