Are Mortise Locksets considered High Security ? - Marks 90

[pingable]

I have a Marks 90 Mortise Lockset.
It's broken....and I need to replace it with either a like (same) locket or one that is compatible with the existing rough-in.

With the said, I'm primarily all Protec on my entrance doors, padlocks, etc.

I am thinking either is it WORTH putting in a Mortise Protec Cyclinder in whatever Mortise lockset I end up replacing it with. The reason is moreso just to maintain the *keying* system I already have.

BTW, for all you gurus out there, anyone know what any lockets are *compatible* fitment wise to a Marks 90 lockset. My current unit is a Marks 90 LHR (RH).