'Bachelor' Finalist Vanessa + Wedding Gown Pic = ???

Vanessa Grimaldi trolled the hell out of 'Bachelor' fans by posing with a bunch of wedding dresses ... but we've learned it was all business -- and NOT Nick Viall business.

Vanessa, one of the last 3 women standing this season, posed for a photo at Le Chateau in Montreal with creative coordinator Holly Wiancko -- and more importantly -- racks full of wedding and bridesmaids dresses.

Naturally, many fans thought Vanessa had just spoiled the final rose ceremony ... that she was already prepping to be Mrs. Viall. Well, you can stop searching for their wedding registry.

Sources connected to Le Chateau tell us the shop invited Vanessa -- who's from Montreal -- to check out their new line and to talk about a partnership once 'Bachelor' wraps. We're told she didn't try on anything from the bridal section.