Is there a way to tell the cookie version via a tcpdump?

You can technically see the "version" attribute in the Set-Cookie header via TCPDUMP, but for the sake of setting the HTTPOnly attribute in an iRule, I've always had problems setting the version and expires attributes using the HTTP::cookie commands. Here's something that should provide what you need:

when HTTP_RESPONSE {
    foreach aCookie [HTTP::cookie names] {
         if the cookie does not already have an HttpOnly attribute
        if { [HTTP::cookie httponly $aCookie] equals "disable" } {
            set value [HTTP::cookie value $aCookie]
            set path [HTTP::cookie path $aCookie]

             insert domain only if it exists
            if { [HTTP::cookie domain $aCookie] ne "" } { set domain "domain=[HTTP::cookie domain $aCookie];" } else { set domain "" }

             insert expires only if it exists
            if { [HTTP::cookie expires $aCookie] ne "" } {
                set expires_local [clock format [expr [clock seconds] + [HTTP::cookie expires $aCookie]] -format "%a, %d-%b-%Y %H:%M:%S GMT" -gmt true]
                set expires "expires=$expires_local;"
            } else {
                set expires ""
            }

             remove the original cookie
            HTTP::cookie remove $aCookie

             insert a new cookie via HTTP header inject
            HTTP::header insert "Set-Cookie" "$aCookie=$value;path=$path;${domain}${expires}HttpOnly;"
        }       
    }
}