Another Taylor Swift wedding rumor just dropped ... and this time, her bodyguard might've accidentally been overtly carrying the evidence!

The security guard was spotted in NYC Thursday accepting delivery of a Stella McCartney garment bag and matching tote ... instantly sparking speculation it could be Taylor's wedding dress ahead of those rumored summer nuptials to Travis Kelce.

Only problem? If it really is the dress, he wasn't exactly treating it like priceless cargo -- dragging the garment bag across the floor and even folding it over at one point while hauling it along.

Still, it seems pretty convincing Stella might be the designer behind Taylor's bridal look ... especially with rumors continuing to swirl the couple could tie the knot July 3 in NYC.

For now though, it’s all speculation -- and Swifties are gonna have to wait to see how it all comes together on the big day ... whenever that may be!