Yes but only on the basis that 55 deg on his gauge doesn't = 80c in real life!!
Best thing is to check the temperature readings while plugged into the Examiner.
For example, my 156 temp gauge is marked 50, then an unmarked mark (if you get my drift), then 90, then others I can't remember.
Following the gauge while on the examiner:
50 = 50
90 = 90
but the mark in between the two is 80
Mine sits close to the "9" of 90 once warmed up.
To confuse the issue even more, failed stats are often masked by failing rads. The over-cooling effect of the stuck open stat is balanced out by the lack of cooling from the failing rad.
As soon as the new rad is fitted it suddenly becomes very obvious that the stat is failed too.
In fact if you are fitting a new rad you may as well replace the stat at the same time and save loosing the coolant twice.