I picked up the U.S. Vista Home Entertainment VHS of War Dog todayjust to see if the release is the MPAA R-Rated edit. Yep, it is unfortunately. I haven't watched the entire tape, but there are edits to the gas station massacre in the beginning. Most notably the complete omission of the children getting shot. I wouldn't be too surprised if there's more butchering since the film goes for gory overkill in the action department.
The unauthorized U.K. DVD under the title War Dog: The Killing Machine is also cut (BBFC link). So this leaves the uncut Japanese VHS (review here) and I presume an uncut Dutch or Greek VHS.