With all due respect, the article states that SNK's 1st title for Wii is this Metal Slug Anthology that will feature almost every Metal Slug ever made along with Wii exclusive features. This implies a standalone product.
If it were for VC, why would SNK announce only one franchise when, like Sega and NEC, they could just announce the whole damn MVS/AVS library? Just the fact that there has been no announcement of MVS VC support prior to the Metal Slug Anthology announcement strongly suggests the former.