If you bought DBC and/or downloaded/registered it with TGC then you will be in their database. Therefore, confirming you are a legitimate owner takes them a few seconds.
If however you bought it mail order elsewhere or from a shop, then confirming this fact would take considerably longer than a few seconds.
When you consider that there could be thousands of users like this out there, I don't think it's unreasonable to assume that it would be a massive undertaking to make the offer available to
every owner of a legit copy of DBC.
Therefore, unfortunately if you aren't on their database, downloading the 2007 version of DBC is not an option. Sorry!
TDK_Man