CO2 Regulator Dial Accuracy, Calibration

I bought a CO2 regulator used a while back and when we first started using it we may have gotten some beer back up into it (for reasons I can't entirely recall). Well we've got it figured out at this point, but I was wondering if there was some way of measuring the accuracy of the regulator's dial, and if so, of calibrating it.

I'm sorry I don't have my equipment here and am not even sure what brand/model etc., so I can't look at it to find out, but here's a not very close up picture: http://picasaweb.google.com/justin.cann/CraigslistHaul/photo#5165916846927541746

First off I would make darn sure the regulator is clean and dry inside without sticky bier in it. Take apart and clean the regulator if it's a quality regulator and throw in a rebuild kit if needed. Add a check valve to prevent future fack flows plus use a good quality pressure gauge to test your regulators gauge readings. Nothing worse than a faulty reading gauge making it a guessing game on your keg pressures. There's a difference in normal products made in China these days vs older made in the USA equipment. There's a reason why this new crap is so cheap and your HBS sells it. it's about profits.