The original studs have an unthreaded portion where they protrude from the filter-housing. I'm not aware of a 'sleeve' there.
If the housing-threads are stripped, a helicoil is an option, but you're still dealing with threads in the aluminum housing carrying the load. Plus you need to buy the helicoil kit and do extra work tapping the Filter-housing ears oversize. Also there's a slight possibility that tapping the ears oversize could weaken them (though this may be insignificant)
In my case, the stud-threads were completely gone, so little or no cutting or drilling was needed to accept a bolt. I already had an an assortment of metric bolts, so it was simple to choose a suitable candidate, grind the bolt head, as a PO had done with the first one, so it could be pushed up from below.
Short of stripping or snapping the bolt itself, or ripping the ears completely off the filter-housing, it's never going to pull loose again.
(At least while I'm maintaining it. Who knows what some oaf at Jiffy-Lube might be capable of!)

Happy Motoring, Mark

__________________
DrDKW