Most VTVMs or FET equivalents allow that. The polarity reversal is needed so that you can measure voltages positive or negative with respect to the chassis with the shield of the cable/probe on the latter (e.g. negative A.G.C. or grid bias voltages, or most voltages on those older transistor units based around PNP transistors). There's normally enough range provided on the zero adjustment (the electrical one, not the mechanical one) to bring the meter up to center zero (with suitable scale provided).
I still have an old Leader VTVM (mid 1960s) which I use for radio work.
And of course, when making that chassis connection you need to make sure it isn't a live chassis, odervize ist spitz und sparken mit poppenfusen!
