The dimension to be aware of was once called “first step to back of heel.” That became a head-scratcher with the introduction of bore-thru designs like the Callaway S2H2. With no heel to measure to…one had to devise a method to determine where it would be had the heel not been ground off. I look for the intersection of the shaft center-line and first scoring line. It is easier for me to see and I can add however much is necessary…usually 3/16 to 1/4. Then, and only then, I return to the “first step to back of heel” dimension and make whatever adjustment the bore depth requires. If, for instance, I have two club heads, each weighing the same, and one has a bore depth 1/4 inch deeper or shallower than the other…I tip trim the shaft so that the “first step to back of heel” is correct. If the iron shaft is step-less…I reference the graphics. After that…just butt trim to playing length and you are good to go. The same holds true if any sort of tip-slug is used. In other words…your suspicion is correct. Bon chance.