Some one in Neogaf posted MGS4 latest numbers.
"Current total in Japan is 660,788, 90.1% sell through (Enterbrain, up to 5 October)."
90% sell through mean Konami shipped around 730k in Japan. Even if Konami doesn't ship more (unluckly) MGS4 did quite well. Now lets compare wih other MGS's LTD.
MGS1: 780k
MGS2: 870k
MGS3: 860k
MGS4: 730k
So even with much smaller install base it did quite well.