The answer is no : if you run the following Magma code : M:=Matrix(Integers(),4,4,[1,0,1,1,0,2,1,2,0,0,5,1,0,0,0,10]); M:=M+Transpose(M); L:=LatticeWithGram(M); H:=GenusRepresentatives(L); for h in H do print "h= lattice with Gram", GramMatrix(h); hd:=DualBasisLattice(h); MD:=37*LLLGram(GramMatrix(hd)); print "rescaled dual = lattice with Gram", MD; a,b:=IsIsometric(h,LatticeWithGram(MD)); print "are isometric : ", a; print " "; end for; on the [online calculator][1], you obtain the following result : h= lattice with Gram [ 2 0 1 1] [ 0 4 1 2] [ 1 1 10 1] [ 1 2 1 20] rescaled dual = lattice with Gram [ 2 0 -1 -1] [ 0 4 -1 -2] [-1 -1 10 1] [-1 -2 1 20] are isometric : true h= lattice with Gram [ 4 -1 2 1] [-1 4 -1 0] [ 2 -1 6 -2] [ 1 0 -2 20] rescaled dual = lattice with Gram [ 2 1 -1 0] [ 1 8 -4 1] [-1 -4 12 2] [ 0 1 2 10] are isometric : false h= lattice with Gram [ 4 1 1 1] [ 1 6 3 1] [ 1 3 8 -1] [ 1 1 -1 10] rescaled dual = lattice with Gram [ 4 1 -1 -1] [ 1 6 -3 -1] [-1 -3 8 -1] [-1 -1 -1 10] are isometric : true h= lattice with Gram [ 2 1 0 -1] [ 1 8 -1 -4] [ 0 -1 10 -2] [-1 -4 -2 12] rescaled dual = lattice with Gram [ 4 1 1 0] [ 1 4 2 1] [ 1 2 6 -2] [ 0 1 -2 20] are isometric : false [1]: http://magma.maths.usyd.edu.au/calc/