The real Boga grip can be certified by the IFGA for record fish. I don't know if the knock-offs can. George has one that he uses, hopefully he'll chime in.
Scott, you are correct. I have used an early Boga for over 10 years and find it very accurate – and also correct that they are IGFA certifiable.
Just to confirm continued accuracy of my Boga, I checked the calibrated weight of a gallon of water and it weighed 8.35lbs – interpolated .25> .... correct weight of 1 gallon fresh water.
I have dunked it in salt and fresh water and it continues accurate – it's a well engineered piece of equipment.
docg, if your Boga is not consistently accurate I would speak with the manufacturer – this is one of the most popular scales in use for sport fishing – and the most “knocked-off”.