Only because JBC insisted he was hit by the second shot. By process of elimination, they would have concluded JFK was hit by the first and third shots. However, they still would have had to wonder why only two bullets were recovered. They would have had to at least offer possible answers for that. The SS recreations would have revealed that JBC was directly in line with a bullet exiting JBC's throat and that might have been enough for them to develop the SBT which would explain why only two bullets were recovered.
Less than two bullets, were recovered. There were more than one and a half bullets missing and it was not possible to say whether the pieces recovered were from the same or separate bullets. So parts of two bullets were missing.
There was CE399 which weighed 157.7 grains which is a few grains less than a full bullet. There was CE567, the nose portion of a copper jacket, which weighed 41.5 grains or about 1/4 of a bullet. There was CE569, the base portion of a copper jacket that weighed 20.6 grains, or about 1/8th of a bullet. (6 HSCA 369)
The Firearms Panel of the HSCA tried to see if CE567 and CE569 were from the same bullet but could not find any matching points :
