Not in my experience. I'm using greylistd with Exim and a custom config which uses geolocation to do greylisting by subnet country code. I've only needed to whitelist a handful of broken MTAs which don't retry.

My spammers clearly haven't caught on yet...

      zgrep grey /var/log/exim4/rejectlog* | rev | cut -c 2-3 | rev | sort | uniq -c | sort -rn | head
      8 CA
      7 IT
      5 ES
      4 BR
      4 AR
      2 TR
      2 RO
      2 IR
      2 EC
      1 PT