It's a comment on the Japanese wikipedia. Anyway, it wasn't Sanjo, it's a comment from Hideki Tajima, who, as far as I know, had no credit in Double aside from the source book with that comment.
Aside from that, everything that he denied was that the medals appearing was a confirmation that Double would guest star in the next show. Not anything about connecting the series or even denying the possibility of guest starring, it was only denied that it was a confirmation that Double would guest star in the following series.
However, one of OOO's producers (Naomi Takebe) said that it was a surprise to see OOO's medals in a Double episode, and joked about Foundation X and Kougami meeting in the future.
Anyway, I guess that what will settle this matter is Movie Wars Core. If it really continues unable to fit into OOO's chronology, there's no way that Double can be in continuity with it, considering how it's clearly canon to Double according to the upcoming Accel movie. However, if it does end up fitting, then Double will obligatorily need to be in continuity with OOO.