There is a comment on page 175 of the 3rd Edition of the Standard Catalog of Smith & Wesson stating that around 1983, 13000 Mod 10's were traded for new firearms and Acusports of Ohio bought many of them.
As far as the designation "Royal" Hong Kong Police, I served in an Navy Shore Patrol unit headquarted at Fenwick Pier in the Wanchi District of Hong Kong in 1962, and again in 1964, and the organization was the RHKP
then.