Are these suckers on plum tree?

I planted a dwarf Opal plum last year and just realised that 2 of the "branches" are probably suckers. They seem to be growing from the trunk itself but Dr Google tells me that any growth from below the "graft union" are suckers which should have been cut off. Is the lumpy bit on the darker stem in the photo (next to the lowest leaf) the graft union?
Thank you.