I recently "sleeved" a Beretta SO that had had an accident. Beretta's are built on a mono block ,so technicaly the gun was "mono blocked" as I was replacing tubes in the original mono block . I did this along with several other guns that were being "sleeved" ie. cutting off the original barrel from the back ends and lumps. As far as I am concerned I SLEEVED them all.
The only diference in the finished jobs , was that the Beretta was not stamped as sleeved by the proof house as the construction of the barrel was unaltered from original ,the others had been.
I hope this may clarify things.