the two i have a different from each other and the markings
they are WAY better than the cheap ones like keg king have
a easy way to use it is to buy the cheap sunding setup, screw off the cheap spund and screw on your good one, it's what i did, i bought two of the cheap ones a while back and upgraded the spund with these from the WEAL bulk buy.
no regrets investing the extra
you could work it off your CO2 reg and come up with the "real" range of your valve
write it down and every now and then re-check
all that said my gauges could be out.... i should swap the valves set at a know set point and test the gauges....