Seems none of these methods to get srid work in v14. The prj is direct input from a valid .prj file and the converted proj string in line 2 looks correct. All the methods to get srid return -1. Why do you have so many methods that appear to be equivalent in the first place?
string prj = "PROJCS[\"WGS_1984_UTM_Zone_15N\",GEOGCS[\"GCS_WGS_1984\",DATUM[\"D_WGS_1984\",SPHEROID[\"WGS_1984\",6378137,298.257223563]],PRIMEM[\"Greenwich\",0],UNIT[\"Degree\",0.017453292519943295]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"latitude_of_origin\",0],PARAMETER[\"central_meridian\",-93],PARAMETER[\"scale_factor\",0.9996],PARAMETER[\"false_easting\",500000],PARAMETER[\"false_northing\",0],UNIT[\"Meter\",1]]\r\n";
string proj = Projection.ConvertWktToProjString(prj);
// None of these methods work!
int srid = Projection.GetEpsgSridByProjString(proj);
srid = Projection.GetEpsgSridByProjString(prj);
srid = Projection.ConvertProjStringToEpsg(prj);
srid = Projection.ConvertProjStringToEpsg(proj);
srid = Projection.GetEsriSridByProjString(proj);
srid = Projection.GetEsriSridByProjString(prj);
Regards,
Damian