Flip Ups - Leupold
Hammer,
I dont know about the Mark 4 scopes. All I know is the VX3 line can have the Alumina accessories. If you have an olde VAri-X III, it can be sent out and have the obj and eyepiece ends threaded at Leupold.
Your best bet is to check out Leupold's website, or try calling Korth Agencies in Okotoks, Alberta ...Leupold's Warranty depot for Canada for answers for your ????.
I hope this helps