Perl

perl -lpe '
   BEGIN{ %h = do{local(@ARGV,$/)=pop;<>} =~ s/^(\s*\d+)(\s\d+)$/$2 $1/mgr =~ //mg;
   $_ .= $h{(/(\s\d+)$/)[0]};
' File1 File2

Bash

while read -r value key; do eval "_h_$key='$value';"; done < File2
while read -r _1 _2 _3 _4 _5; do
   eval "x=\$_h_$_5"
   printf '%s ' "$_1" "$_2" "$_3" "$_4" "$_5"
   echo "$x"
done < File1

Сед

echo '.' >> File2
sed -e '
   1{
      :file2
         N
      /\n\.$/!bfile2
      H;d
   }
   G
   s/\([ ][0-9][0-9]*\)\n.*\n\([0-9][0-9]*\)\1\n.*/\1 \2/
' File2 File1