Your seeing those lines in the firewall logs does not mean that you're vulnerable, only that some out out there thinks that you might be. To that effect, but that is only my opinion and I had several experts disagree vehemently, having your server hide its versioning tokens might be counterproductive, because would-be exploiters will try all their tricks - those you might be vulnerable to, and those you aren't. If an exploit against Foo Script comes out, you won't be spared just because you aren't advertising your usage of Foo Script.