For tagging purposes, the tag Vespa P-Series is fairly reduandant since it is visually similar to the other Vespa model and does not have any distinctive features. So I think it should be deprecated.
Meanwhile, the Vespa 150 TAP is a specifically modified Vespa with recoiless rifle. Since this vehicle is quite well-known for its distinctiveness, I think this tag should be kept and imply with the main Vespa tag.
(I was unable to made an edit requests since both tags have less than 10 posts.)