Lacquer was still used on sunburst into the '70s.
Even then they were using poly as the undercoat not fullerplast or whatever they called it prior. So it was a thick poly undercoat with the nitro on top. From what I have seen that went into 72 and not a whole lot further. So I guess its possible but I still call them all poly finishes at that point based on the way they were doing them.