Is it possible to determine what tissue a DNA sample came from based solely on its sequence?
The answer is in the question but I suppose you wanted to ensure you were not missing some info.

Answer

The DNA sequence is the same in all cells of a multicellular organism. Only the expression pattern varies among tissues. It is therefore impossible to tell from the DNA sequence alone what tissue a cell come from.

It would be feasible by looking at the transcriptome or the proteome or eventually by looking at epigenetic modifications.

Potential exception

Of course, as you talk about CNV, if you consider that the number of chromosome is part of the info present in a DNA sequence, then haploid cells (spermatozoids and ovules) are an exception and you could tell them apart. Similarly anucleated cells would be an exception as they contain no nuclear DNA.

Further potential exceptions are explained by @tsttst in his comment.