The distinctive presentation of the 'rag & bone' brand name, in lowercase letters with a typewriter font is a logo in and of itself. However, the lesser known 'rb' icon logo (shown below) is where counterfeiters most often run afoul and is the best place to start when authenticating Rag & Bone jeans.
Rag & Bone always positions this icon logo in the upper right corner of the back right pocket on their jeans. And it is always stitched onto the jeans, never printed. If you find a pair that omits this logo, positions it incorrectly, or prints the logo – then it is certainly a fake. RUN FOR THE HILLS. Take, for example, this pair of Rag & Bone jeans. Notice anything different between the authentic pair on the left and the fake on the right?
Rag & Bone uses metal zippers made by Yoshida Kogyo Kabushikikaisha, better known as YKK. A genuine YKK zipper is easy to spot because it'll have the YKK initials printed on the zipper itself (both on the pully and the under-side of the body). If you see a purported Rag & Bone jean without a YKK zipper or using a material other than metal such as coil or plastic then it's a fake.
Front button closure and rivets should share the same metal tone color and embossed with the brand's name or logo, which may vary. Luxury brands like Rag & Bone pay careful attention to detail and an oversight such as copper rivets with a silver button closure wouldn't occur and is a sign of a fake.
Lastly, Rag & Bone always includes a number of tags on the inside waistband of its jeans, which can generally be identified as: (1) size tag, (2) brand tag, and (3) fabric tag. Notably, the size tag is proportionately smaller than the other two tags and the content (i.e. the size) is stitched on rather than printed on. Any deviation from this would be a sign of a fake.
The fabric tag (shown on the left next to the size tag) and the brand tag (shown on the right) are both printed-inscribed and larger than the size tag.
The fabric tag will include the style/model number and the color. To authenticate, try running a Google search stating the brand name (Rag & Bone) and the style/model number and check to see if the results match the product in your hand. Often times counterfeiters will mass produce different styles using a single style/model number tag, resulting in inconsistencies between the tag description and the actual product itself.