Wellogate may have a section with the majority of burials around 1929 towards the middle to back not on the highest areas, but in general burials are mixed around the cemetery, depending on family plots and available liars/space.
Best to check with the town hall about the liar book, it used to be kept at the cemetery lodge years ago, but I think it know at the Town Hall.
William Robb may be buried in Hawick,but try Teviothead and Newmill area first.
There is a record at the Hub of some of the old gravestones at the Wellogate and St Mary's Church printed around the 1930's, but not sure if graves around 1929 are included.
best of luck