I'm very weak in immunology, but when an antigen is encountered in vivo it is handled by the immune system in one of two different pathways: cross-linking or presentation by an APC (Antigen Presenting Cell).
If your detecting antibody was derived from the latter pathway, then the protein had already been denatured by the APC when the antibodies were developed, therefore denaturing with SDS should be the same as denaturing by the APC.
Bottom line: if your protein of interest is viral or self-protein, and the antibody was developed in a different species, then it should be recognized by the antibody, whether it is contiguous or not. Doesn't that seem correct?
PS I have zero experience with Westerns, this is a conjecture on my part. Rock on, Randy