Yes, that could be but keep in mind several factors that can affect this.

For example, during one of my many tests I used a Yo-zuri Mag Darter as a point of reference.  The plug is listed as 6.5".  I added that as a new reference in the app and when I calculated the length of a Bluefish, the measurement had come in a couple of inches of what I had manually measured using an actual ruler.  After a closer look the plug, not including any hardware, the length came to approximately 6.30".  I remeasured it using the updated length of the reference object and the measurement was now exactly the same as I got using a ruler.

The weight estimates are derived from tables that were pre-loaded into the application.  Nothing is going to be as accurate as a certified scale; however, the charts can be pretty accurate.  A fishing buddy caught a Striped Bass that measured 43" and weighted 27.5 lbs on his Boga Grip scale.  Prior to that I had caught a skinny 43" Striped Bass that we estimated to be around 27lbs.  This example tells me my original estimate of the weight of that fish was pretty accurate.

These charts can be updated so please feel free to reach out to me with any updated conversions.  Thanks.