Brandon,
I didn't check that... although I found an easier solution. I had the same issue with a custom table we added, and instead of deleting the whole table I deleted all the table's records in the SQLDICTIONARY, thinking these would be re-generated when I synchronized. I was right, the SQLDICTIONARY records were regenerated and the table was able to sync without further issues.
I wonder if the legacy Id(s) were the issue. Running the live upgrade this weekend, I'll let you know!