I've got 6.004 and 6.005, but not 6.003
Interestingly enough...when I thought that I had lost my 6.005 archive I wasn't able to get a copy from BoonEx. I was fortunate that I had found it on a different thumb drive. If you would like me to provide a temporary download link for 6.004 or 6.005, I can do that for you.
I half disagree with Sammie's comment about just moving forward and abandoning the mods and templates which you have bought. My employers site http://www.motospace.com runs on 6.005 and when the script kiddies were defacing/attacking all the sites running the new version...our site was unaffected.
Any security risk can be mitigated through the proper configuration of your PHP.INI or .htaccess files OR in the case of insecure code...making it secure.
Granted these risk mitigation steps aren't for the average Dolphin administrator, but for those 'IT People' (like myself) they are a very plausable option. Let me know if you still need that 6.004 or 6.005 download link.