]www.ruger-firearms.com/hgpages/kmk678gc.html]
]www.gunblast.com/Ruger_50th.htm]
I could not find anything on a limited edition slab-side Mark II.
"Alex Sturm himself, who was a student of heraldry, originally designed Ruger’s distinctive trademark “phoenix” logo, and at the company’s inception the grip medallions featured a red phoenix. Upon Sturm’s untimely death in 1950, Ruger ordered that henceforth the grip medallions would no longer feature a red phoenix, in memory of his friend and business partner. The medallions were initially changed to feature a black phoenix, and over the years a silver phoenix on a black background became the standard. The 50th Anniversary Model invokes the spirit of the original medallions by featuring a silver phoenix on a red background. This logo is also set into the bottom of the two magazines that are included with each gun (nice touch, Ruger!).